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Undergrowth is ground cover plant which is generally in the form of herbs, grass or low shrubs. Mostly undergrowth is flowering plants. The Flower is part of plant for generative reproduction that consists of several organs that consist of pedicellus, receptacullum, perianthium, pistillum and stamen that contain pollen. Pollen is part of the flower that functions as a generative reproduction agent because it contains male gamete. Pollen has a distinctive character in each plant so that it can be used as a tool for identifying plants. Sampling location was conducted in Bantarbolang Nature Reserve, a conservation area located in Kebon Gede Village, Bantarbolang District, Pemalang Regency. The objective of research is to know the morphological character of undergrowth pollen in the Bantarbolang Nature Reserve. The research used a survey method with explorative sampling techniques. The variables that observed are the morphological character of pollen with the parameters consist of pollen unit, shape, aperture, diameter, and ornamentation. Sample preparation uses the acetolysis method and descriptive data analysis. Based on the results of the research found 6 species of undergrowth with different pollen morphological characters in the pollen shape (sub-speroidal and prolate), aperture (tricolpate, tricolporate and fenestrate) and ornamentation type (psilate, reticulate, perforate and echinate). The pollen units of all species have the same type, monad

Pollen morphology of 27 species of Photinia sensu stricto and five closely related genera of subfamily Maloideae (Rosaceae) were studied in detail. Palynomorphological characteristics were examined using scanning electron microscopy (SEM). Comparative pollen analysis was accomplished based on pollen size, shape, polar and equatorial views, polar and equatorial diameter ratio (P/E ratio), width of aperture, and exine ornamentation. The pollen grains of studied species were found to be monad, tricolporate, small to medium in size (P=17.42–30.45 μm, E=9.26–20.18 μm) and to have shapes oblate-spheroidal (0.88–1.0 μm), prolate-spheroidal (1.01–1.14 μm), sub-prolate (1.15–1.33 μm), prolate (1.34–2 μm), and perprolate (>2 μm). The exine ornamentation was perforated-striate, and two different types were identified. The result of quantitative characters has paltry taxonomic importance. The characters studied here delimit at generic level for some genera but not at species level. The obtained result was partially consistent with that of molecular studies published earlier. The pollen size and shape were found to be different between Asian and American species of Photinia. Especially exine sculpture was found to be an important feature to distinguish species of all genera studied. PCA analysis showed that the pollen shape, pollen sculpture, pollen size, and polarity are the key characters to distinguish the species of Photinia and the closely related genera in subfamily Maloideae. Based on pollen exine, two groups (Type I and Type II) were distinguished. The aim of the present study was to find out the taxonomic significance of palynomorphological characteristics in subfamily Maloideae (Rosaceae).

The characterization and viability of pollen grains are useful tools to guide crosses in breeding programs. The objective of this study was to describe the morphological patterns and viability of pollen grains from five accessions of Passiflora edulis f. flavicarpa O. Deg. and five accessions of Passiflora setacea DC. Pollen morphology descriptions were made using light microscopy and scanning electron microscopy, whereas the viability analysis was performed by in vitro germination and histochemical analysis (Lugol's solution and 2,3,5-triphenyltetrazolium chloride). Pollen grains assessed for germination were inoculated in culture medium containing Ca(NO3).4H2O (0.03%), Mg(SO4).7H2O (0.02%), KNO3 (0.01%), H3BO3 (0.01%), sucrose (15%) and agar (0.8%). Although P. edulis and P. setacea showed the same shape and type of pollen aperture, the two differed in terms of their morphology and exine ornamentation pattern. In vitro analysis showed that one of the P. edulis f. flavicarpa accessions (designated BGP 330) presented the highest germination rate (53.98%) and longest pollen tube (2.18 mm). The histochemical analysis overestimated pollen viability when compared with the in vitro results. The results of this study contribute to the breeding of Passiflora species by increasing the understanding of their morphology and pollen grain viability.

Pollen morphology of 24 Brazilian species of Codonanthe and Nematanthus (Gesneriaceae) was investigated by means of light microscopy, scanning and transmission electron microscopy, in search of new characters that might contribute to taxonomic characterisation of the genera. The pollen grains are tricolpate or tricolporate, semitectate, reticulate, with simplicolumellate muri, sometimes with microreticulum and perforations, or duplicolumellate muri ring-shaped around lumina. The species studied were grouped into five pollen types on the basis of aperture characteristics and details of surface ornamentation. Sub-types were defined with reference to presence or absence of microreticulum and perforations around the lumina. Based on analysis of the morphology and measurements of pollen grains, we verified a close relationship among the genera, but can nevertheless discriminate their species.

Pollen morphology of 38 Trigonella species was investigated with light microscopies and scanning electron microscopies. Pollen slides were prepared using Wodehouse technique. The pollen grains of Trigonella members are radially symmetrical and isopolar, their outlines are oblong in equatorial view and circular in polar view. Amb is semicircular. The pollen grains are prolate-spheroidal, oblate-spheroidal, suboblate, spheroidal, and prolate with the polar axes 13.5-49.9 mu m and the equatorial axes 10.4-43.7 mu m. The smallest dimensions are observed in T. spinosa and T. brachycarpa, and the largest in T. carica and T. rhytidocarpa. The pollen grains of Trigonella taxa are usually tricolporate or rarely tricolpate, pantocolporate, tetracolporate, and tricolpodiporate. Various ornamentation types were observed: Microreticulate (section Samaroideae, Pectinatae, Falcatulae, Cylindricae, Bucerates, Reflexae, Isthmocarpae, Capitatae and Foenum-graecum), rugulate-scabrate (section Lunatae, Uncinatae), perforate (T. halophila, T. rigida and T. carica from section Bucerates) and retipilatae (section Biebersteinianae) at equator region and psilate-perforate (section Samaroideae, Pectinatae, Bucerates, Reflexae, Isthmocarpae, Foenum-graecum, T. coelesyriaca, T. cilicica), rugulate-scabrate (section Lunatae, Uncinatae), microreticulate (Falcatulae, Cylindricae and Foenum-graecum) and retipilatae (section Biebersteinianae) at polar region. Ornamentations, pollen shape and the aperture type have been observed as important morphological characters.

We analyzed the pollen grains of 30 taxa of the genus Bauhinia L., within five series: Aculeatae (9 species); Acuminatae (1 species); Cansenia (17 species); Pentandrae (2 species); and Perlebia (1 species). The pollen grains were acetolysed, after which they were photographed and analyzed under light microscopy. Non-acetolysed pollen grains were analyzed under scanning electronic microscopy. Characters such as shape, size, exine and aperture constitution were studied. The species were separated by a dichotomous key, which showed pollen grains that were classified as very large; isopolar or apolar; oblate, suboblate, oblate spheroidal or spherical; large or small in terms of the polar area; inaperturate, 3-porate or (3-7)-colpate; and microreticulate or reticulate, with or without supratectal elements (gemmae, bacula, clavae). The variation in pollen morphology confirms the eurypalynous status of the genus Bauhinia.

The evolution of the apertural type in the ANITA-grade family Nymphaeaceae, despite the importance of pollen characters for both palaeobotanical and neobotanical investigations, has not been yet totally understood. To elucidate some unclear aspects regarding the homologies of the apertural condition in basal and core Nymphaeaceae, we examined the pollen grains from five species of this family. We offer for the first time some evidence about the presence of a proper operculum in the pollen grain of Nuphar and for the ring-like status of the aperture of Nymphaea caerulea and Victoria cruziana. Our findings clarify and reinforce the hypothesis of an opercular origin of the distal part of the pollen grain in the core Nymphaeaceae and support the paraphyly of the genus Nymphaea as emerged from recent molecular studies. The diversity and specialisation of this 'basal' family is underlined even by its pollen characters. © 2013 Copyright Collegium Palynologicum Scandinavicum.

Pollen morphology of 20 species of Euphorbioideae and one from Crotonoideae was examined with light, scanning and transmission electron microscopy. The pollen morphology presented here did not support the monophyly of Euphorbioideae, and the unique characters of tribe Stomatocalyceae such as absence of aperture margins, and thick and continuous endexine suggest the exclusion of Stomatocalyceae from Euphorbioideae which is in accordance with previous phylogenetic studies and wood anatomical data. Aforementioned pollen features in this tribe support that it is closely related to Acalyphoideae. Two subtribes of Stomatocalyceae were well recognized in terms of pollen morphology: Hamilcoinae includes species with reticulate or microreticulate exine patterns, and Stomatocalycinae includes those with perforate patterns with small supratectal elements. Three subtribes of Euphorbieae, classified in terms of pollen morphology, were further divided into three different types including perforate in Euphorbiinae, microreticulate in Neoguillauminiinae and reticulate in Anthosteminae, strongly supporting the Webster`s subtribal system. Hureae and Hippomaneae, having perforate sculpturing pattern with smooth margo, were similar in pollen morphology. Especially, the presence of small supratectal elements in Hura crepitans pollen suggests the close relationships with Excoecaria species of tribe Hippomaneae. According to the previous studies, unique intine thickness along the aperture margin in Euphorbieae was not reported elsewhere in Euphorbiaceae. However, in this study we found the same intine thickness along the aperture margin in Maprounea brasiliensis and Hura crepitans. We hypothesize that the similar intine thicknesses found in Euphorbieae and above two species are the evidence of close relationships among them.

Anatomical, palynological, karyological and morphological seed characters of Silene brevicalyx and S. ozyurtii (Caryophyllaceae) were investigated for the first time. S. brevicalyx grows on serpentine rocky slopes and open forest in Muğla province (southwestern Turkey), while S. ozyurtii is an East Mediterranean element growing on serpentine stony slopes and again open forest. Anatomically, cross-section of root of both species have a periderm as the protective tissue at the outermost layer and locally druse crystals are encountered in cortex layer. Stems have a thick well-developed sclerenchyma layer. The walls of outward sclerenchyma cells are wider than the walls of inward cells. Leaves are equifacial. Pollen are prolate-spheroidal, symmetry radially, polarity apolar, with aperture periporate, ornamentation microechinate-perforate. Seeds of both species are reniform, with surface concave and granulation coarse-medium, hylar zone recessed, dark-brown or fuscous coloured. Somatic chromosome numbers of 2n = 24 were found for both taxa. The karyotypes are analyzed for the first time for S. brevicalyx and S. ozyurtii. Ideograms of these taxa were drawn by use of an Image Analysis System.

IN the formation of the exine of the pollen grain, the highly resistant wall polymer, sporopollenin, is laid down in a series of layers. Of these, the outer, the sexine of Erdtman's terminology1, is often strongly sculptured. Sexine pattern may have high taxonomic specificity, and because the sculpturing is executed in so refractory a material, the morphogenetic processes concerned are of considerable interest. Rowley and Southworth2 have shown that in the formation of the inner exine layer near the germinal aperture of the microspore of Anthurium sp., sporopollenin is deposited on lamellae of “unit membrane dimensions”. The superimposition and compaction of these lamellae as the coating of sporopollenin thickens produce the layer corresponding to the nexine 2. Essentially the same process has been described and illustrated by Godwin et al.3 in the growth of this stratum in Ipomoea purpurea. It is clear from various earlier reports4–7 that the inner exine layer may often reveal lamellation even at maturity, indicating this kind of origin. The sexine and nexine 1, formed earlier than the nexine 2, usually reveal no lamellation, and Godwin et al.3 were forced to conclude that these parts of the exine have a different mode of origin. We show in this communication that all strata of the exine of Lilium longiflorum originate through a process involving the association or apposition of lamellae. Because the lamellae are generated near the plasmalemma, the observation re-emphasizes the role of this membrane and the cortical cytoplasm in the determination of exine pattern.

Pollen morphology of Cornus mas L. and Cornus sanguinea L. Abstract: The pollen morphology of 2 species of the genus Cornus L. distributed in Turkey was studied with light and scanning electron microscope. The pollen of genus Cornus is 3-colporate. Pollen of the Cornus mas is spheroidal and Cornus sanguinea is subprolate. Size varies of Cornus mas pollen with the polar axis ranging from 21.54 to 27.36 μm and equatorial axis from 21.31 to 26.72 μm. Size varies of Cornus sanguinea pollen with polar axis ranging from 54.41 to 71.69 μm and equatorial axis from 46.03 to 63.42 μm. The equatorial outline of Cornus mas pollen is triangular and Cornus sanguinea pollen is circular. The results showed that pollen of these two species can easily be identified as species level. Keywords: pollen morphology, Cornus mas , Cornus sanguinea . Cornus mas L. ve Cornus sanguinea L. turlerinin polen morfolojisi Ozet: Turkiye’de yayilis gosteren Cornus L. cinsinin 2 turunun ( Cornus sanguinea L. ve Cornus mas L.) polen morfolojisi isik ve taramali elektron mikroskobuyla calisilmistir. Cornus cinsinin polenleri trikolporat aperture sahiptir. Cornus mas ’in polen sekli sferoid iken Cornus sanguinea ’nin ise subprolat’dir. Cornus mas polenlerinin polar eksen uzunlugu 21.54-27.36 μm ve ekvatoral eksen uzunlugu 21.31-26.72 μm arasinda degismektedir. Cornus sanguinea polenlerinde ise polar eksen uzunlugu 54.41-71.69 μm ve ekvatoral eksen uzunlugu 46.03-63.42 μm arasinda degismektedir. Cornus mas ’in ekvatoral dis gorunusu ucgenimsi iken Cornus sanguinea ’nin ise dairemsidir. Elde edilen sonuclar bu iki turun polenlerinin kolaylikla ayirt edilebilecegini gostermistir. Anahtar Kelimeler: Polen morfolojisi, Cornus mas, Cornus sanguinea Received (Gelis): 13.04.2016 - Revised (Duzeltme): 03.08.2016 - Accepted (Kabul): 12.08.2016 Cite (Atif): Karlioglu Kilic, N., Tuttu, G., 2017. Pollen morphology of Cornus mas L. and Cornus sanguinea L. Journal of the Faculty of Forestry Istanbul University 67(1): 65-71. DOI: 10.17099/jffiu.75357

Pit connection formation in the marine red alga Pseudogloiophloea confusa was studied with the electron microscope. The process of formation occurs in 2 stages. First, a septum forms as an annular ingrowth from the lateral walls. Lomasomes are associated with the centripetal accretion of wall material. The completed septum contains a large rimmed aperture, bounded by the continuous plasmalemma, and through which the cytoplasm is continuous from cell to cell. In the second stage, a highly structured plug is formed which completely blocks the aperture. The plug is condensed on flattened vesicles which lie parallel to one another and which traverse the aperture. The mature plug is composed of granules 50-100 A in diameter and surrounded by several dense layers which appear to enclose an 80 A limiting membrane. Once the pit connection is formed, no material is seen to traverse it.

Pollen tetrads and monads of spiny pollen grains with close affinities to palms have been found in several localities from the Lower Cretaceous (Barremian-Albian) of the Austral Basin (Magallanes), Patagonia (Argentina). When found dispersed, spiny and zonasulcate pollen grains, are commonly referred to the fossil genus Spinizonocolpites Muller, with close affinities to the extant palm Nypa. The Patagonian specimens were compared with fossil and extant members of the Arecaceae, showing close similarities in shape and sculpture with the primitive members of the subfamily Calamoideae. Nypa produces tetragonal tetrads different from the tetrahedral tetrads of the Spinizonocolpites-type recovered from Patagonia. The specimens were studied with LM and SEM. The polarity, aperture orientation and tetrad type allow segregating the Patagonian grains from the Nypoideae and relating it to the Calamoideae subfamily. These records suggest an antique origin of monocots and a probably initial diversification of calamoid palms during the Early Cretaceous in high latitudes of Gondwana. The presence of palmae during the Early Cretaceous in southern South America suggests a warm and humid climate, similar to that found in present days at tropics. Fil: Martinez, Leandro Carlos Alcides. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Archangelsky, Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Pramparo, Mercedes Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: Archangelsky, Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina

Study was aimed to investigate the effect of industrial air pollution on pollen morphology of Eucalyptus globulus Labill. , belonging to family Myrtaceae. Data revealed that there are differences in pollen morphological characteristics of E. globulus that grows in polluted industrial area in comparing with the pollen of that plant grows in healthy conditions (control area). Eucalyptus pollen grains are flattened triangular- obtuse- convex shape in polar view (the only view that is usually present). Aperture ( trizonocolpate- syncolpate), colpi fusing in each apocolpium to cut off an island of exine shaped like a triangle. Sculpture, psilate. The LM and SEM studies revealed that pollen grains of the control area showed normal size, shape and sculpture. While in case of polluted industrial one there is a shrinkage in size, thinning of exine, protrusion elements on the pollen surface, some attached particulate materials on the pollen surface ; that may be affected due to air pollution.

The pollen morphology of 28 Begonia species of Nepal has been examined by scanning electron microscopy (SEM). Comparative pollen analysis was made based on size, shape in polar and equatorial views, P/E ratio, aperture, and exine ornamentation. In this study, four types of pollen ornamentation morphology have been identified. Among Nepalese Begonia , B. roxburghii (section Sphenanthera ) has the smallest pollen (11.2- 12.8 × 6.4-7.0 μm) and B. flagellaris (section Diploclinium ) has the largest pollen (24.3- 30.6 × 11.4-12.0 μm). Presence of margo in the pollen ornamentation is a distinguishing character that separates Begonia section Platycentrum from all other sections of Nepalese Begonia . DOI: http://dx.doi.org/10.3329/bjpt.v19i2.13134 Bangladesh J. Plant Taxon. 19 (2): 191-200, 2012 (December)

Pollen morphology of seven taxa of Kalmia was examined using light and scanning electron microscopy (LM and SEM, respectively), or SEM alone, in search of new characters that might contribute to infrageneric classification of the genus. The Kalmia species are stenopalynous and characterized by 3-colpor(oid)ate, medium, oblate pollen united in tetrahedral tetrads with rugulate exine sculpture. However, a continuous and serial variation in all the quantitative characters and exine sculpture was revealed within the genus. Kalmia buxifolia is characterized by having the smallest pollen tetrads, largest aperture, largest 2f/D ratio and septum thicker than apocolpial exine. On the other hand, K. latifolia produces the largest pollen tetrads with smallest aperture and smallest 2f/D ratio. An evolutionary trend from rugulate to psilate has also been observed in apocolpial exine sculpture of the genus Kalmia. On the basis of acetolysed pollen characteristics, a dichotomous key for Kalmia was prepared. DOI: http://dx.doi.org/10.3329/bjpt.v19i2.13126 Bangladesh J. Plant Taxon. 19(2): 123-133, 2012 (December)

The pollen morphology of eight taxa representing Pinus species of Pinaceae in northeast China was examined by light microscopy and scanning electron microscopy. The pollen grains were bisaccate monads. A single elongate outlined (monosulcate) aperture was observed on the distal pole between the sacci (air sacs) and the sculpture pattern of the corpus (pollen body) was verrucate or rugulate, while sacci were foveolate on either smooth or coarse surfaces. A key to pollen types of Pinus in northeast China was developed based on whether the sacci outline in polar view was discontinuous (diploxylonoid) or continuous (haploxylonoid) with the corpus outline, and on the exine sculpture patterns on the corpi and sacci. The pollen types were Densiflora, Koraiensis, Sylvestris, and Tabulaeformis. The pollen width with sacci was highly correlated with the corpus width.

A protruding oncus is a projection of the intine in the aperture region. The ubiquitous use of acetolysis in palynological research has led to the presence of a protruding oncus being underreported. Controlled experiments with pollen samples collected from undehisced and dehisced anthers demonstrate that the presence of a protruding oncus is affected by the state of the anther at maturity: dehisced or undehisced and by the preparation technique. In investigating the occurrence of onci, particular attention should be paid both to the dehiscence state of the anthers and the effect of the preparation technique on the intine. Although it has been suggested that protruding onci and pollen buds can be distinguished based on three criteria (size, presence of a large vacuole, separation of the protrusion from the grain), most of these distinctions break down when information is included from more recent studies. Additional study of protruding intinous structures may help clarifing the difference between ...

The structure of receptacular surfaces of floral nectaries at two flowering stages and the structure of the outer surface of the receptacle of Sorbus aucuparia were investigated using scanning electron microscopy. Changes in the development of the cuticular epithelium of the nectary epidermis and differences in the degree of aperture of stomata were observed. Increased undulation of the gland surface was found during flower development. Numerous stomata were situated slightly below the level of epidermal cells of the nectary. At the pollination stage, open pores or pores surrounded by the cuticular epithelium were observed, as well as covered by dried secretion. Dried nectar in the form of patches was also visible on the surface of the gland. Stomata of the outer surface of the receptacle were located on protrusions and surrounded by the cuticular epithelium.

Xyridaceae are a predominantly tropical family of five genera that exhibit two pollen morphologies often considered to be of taxonomic importance. Xyris comprises about 95% of the species and is characterized by medium to large, elliptic, sulcate pollen grains. The other pollen class is spheroidal grains without an evident aperture. Many of the species with spheroidal grains have remarkably large and ornamented pollen found to be species specific in earlier research. A scanning electron microscopy investigation of 23 taxa representing all genera with spheroidal pollen revealed new data to further distinguish the genera based on pollen characters. Reliable specific pollen characters need to be evaluated in a statistical study.

Over nineteen species of pollen flora belonging to thirteen families were recovered from four pollen load samples from honey bee Apis cerana collected in Jajarkot district, mid-western region, Nepal. The pollen morphology was investigated using light microscopy along with scanning electron microscopy for correct identification of pollen to its lower taxonomic level and to contribute to melissopalynological studies originating from the native apiflora. The palynological assemblage identified to the generic and some up to species level belong to Alnus sp., Artemisia sp., Brassica sp., Cornus sp., Diploknema sp., Fraxinus sp., Ilex sp., Jasminum sp., Justicia sp., Ligustrum sp., Myrica esculenta , Salix sp., Strobilanthes sp., and Urtica sp. Some of the pollen grains identified to only family level, belong to, Acanthanceae, Compositae, Lamiaceae and Rosaceae. The identified pollens clearly reflect the botanical and geographical origins of the pollen load samples. Palynomorphological investigation included the description of pollen symmetry, polarity, ornamentation, aperture, shape and size. The results for the pollen assemblages and nectariferous plant sources of Jajarkot district are discussed. DOI: http://dx.doi.org/10.3126/njst.v12i0.6522 Nepal Journal of Science and Technology 12 (2011) 340-349

The pollen morphology with special reference to exine sculpturing of four species of the genus Pedicularis L. has been examined by light and scanning electron microscope. Comparative pollen analysis was made based on the type of pollen, shape in polar and equatorial views, P/E ratio, exine thickness and sculpturing of pollen. In this study, two types of pollen aperture configuration known in the genus were observed i.e., trisyncolpate and bi-syncolpate. Pollen grains with microscabrate ornamentation were found in bi-syncolpate pollen for the first time. Pollen fertility estimation ranged from 87-95%, which shows that pollen flora of selected species is well established in Alpine zone.DOI: http://dx.doi.org/10.3329/bjpt.v19i1.10935Bangladesh J. Plant Taxon. 19(1): 1-5, 2012 (June)

The pollen of the wild species from the genus Crocus L., spread in Bulgaria has been analyzed. The investigations, made by light microscope show that the pollen of these species is spherical in shape and round in outlines, comparatively big. These morphological characteristics of the pollen of the wild Bulgarian Crocuses define it as a primitive one [6]. The Scanning Electron Microscope investigations, made by Beug [1], established two types of pollen morphology. The results of our investigation led to the conclusion that the same types are also presented in Bulgarian species: – C.biflorus –type, or syncolpate and C.vernus – type, or inaperturate. Eight of the species belong to the first type and only C. pallasii belongs to the second. The pollen of C. reticulatus is with quite unclear aperture – maybe transition to the inaperturate type.

Microspore and megaspore development in Isoetes japonica was studied using light, scanning electron and transmission electron microscopy. Differences in cytokinesis following meiosis result in monolete microspores with bilateral symmetry, and trilete megaspores with radial symmetry. Wall development follows essentially the same sequence in both microspores and megaspores, but with the wall of the latter being very much thicker. A significant difference was observed in the tetrad stage, when microspores have an essentially rounded outline with the plasma membrane folded into a crest at the site of the future aperture. Megaspores in the tetrad stage are strongly invaginated over their entire surface, creating numerous crests, and this appears to have a role in determining the morphology of the perispore. The outline shape of the megaspore perispore having been established in the tetrad stage, most of its substance is added later and is derived from the degenerating tapetum.

The paper presents the performance of an evacuated tube heat pipe solar collector compared to a concentratedevacuated tube single-sided coated heat pipe absorber for medium temperature applications.The aperture areas of the solar collectors were 0.107 m2 and 0.2004 m2 for the evacuated tube heat pipeand the concentrated evacuated tube single-sided coated heat pipe absorber, respectively. Experimentswere conducted at five different transverse angles (0–40◦) with a collector title angle of 60◦ to the horizontal.These solar collectors were tested over a range of operating temperatures and the mean fluid andambient air temperature differential increase and outlet and inlet fluid temperature differential, energycollection rates and efficiency and the heat loss coefficients of each solar collector was experimentallymeasured, calculated and compared to each other. The concentrated evacuated tube heat pipe solar collectorshowed an improvement of 30% and 25.42% in overall average outlet and inlet fluid temperaturedifferential and total daily energy collection, respectively compared to the non-concentrated evacuatedtube heat pipe collectors.

Although much attention has been paid to the role of stabilizing selection, empirical analyses testing the role of developmental constraints in evolutionary stasis remain rare, particularly for plants. This topic is studied here with a focus on the evolution of a pollen ontogenetic feature, the last points of callose deposition (LPCD) pattern, involved in the determination of an adaptive morphological pollen character (aperture pattern). The LPCD pattern exhibits a low level of evolution in eudicots, as compared to the evolution observed in monocots. Stasis in this pattern might be explained by developmental constraints expressed during male meiosis (microsporogenesis) or by selective pressures expressed through the adaptive role of the aperture pattern. Here, we demonstrate that the LPCD pattern is conserved in Euphorbiaceae s.s. and that this conservatism is primarily due to selective pressures. A phylogenetic association was found between the putative removal of selective pressures on pollen morphology after the origin of inaperturate pollen, and the appearance of variation in microsporogenesis and in the resulting LPCD pattern, suggesting that stasis was due to these selective pressures. However, even in a neutral context, variation in microsporogenesis was biased. This should therefore favour the appearance of some developmental and morphological phenotypes rather than others.

The general morphology, surface sculpturing, and exine ultrastructure have been studied in dispersed monosulcate pollen from the Early Cretaceous of Transbaikalia, Russia. The pollen grains dominate the palynological assemblage extracted from coal deposits of the Khilok Formation in the Buryat Republic, which also contain ginkgoalean leaves of Baierella averianovii as the only constituent of the assemblage of plant megafossils. The relationship between the pollen grains and ginkgoalean leaves from this autochthonous burial is hypothesised on the basis of taphonomical analysis and palaeobiogeographical data. It is shown that the ectexine of the pollen grains includes a thick solid tectum, a thin granular infratectum and a thin foot layer; the endexine is fine-grained, slightly more electron-dense than the ectexine, and is preserved only in places. The distal aperture is formed by a thinning of the exine. No analogous ultrastructure has been described so far in fossil pollen grains of this morphoty...

O município de Mirandiba, Pernambuco, foi considerado como área prioritária para a conservação da Caatinga e apresenta uma grande diversidade florística. Leguminosae desponta como família mais diversa, representando cerca de 25% das espécies conhecidas para o domínio. Foram caracterizados os grãos de pólen das subfamílias Caesalpinioideae e Papilionoideae, e estabelecidos grupos com afinidades na morfologia polínica. Em Caesalpinioideae, são discutidas diferenças especialmente quanto à ornamentação da exina, marcantes entre os gêneros estudados. Enquanto em Papilionoideae, a variação mais marcante está no tipo de aberturas, sendo encontrados poros, cólporos e colpos. Nas duas subfamílias, a maioria dos gêneros pode ser considerada estenopolínica, restringindo o reconhecimento de espécies por caracteres apenas morfométricos.

Pollen transport to a receptive stigma can be facilitated through different pollinators, which submits the pollen to different selection pressures. This study aimed to associate pollen and stigma morphology with zoophily in species of the tribe Phaseoleae. Species of the genera Erythrina, Macroptilium and Mucuna with different pollinators were chosen. Pollen grains and stigmas were examined under light microscopy (anatomy), scanning electronic microscopy (surface analyses) and transmission electronic microscopy (ultrastructure). The three genera differ in terms of pollen wall ornamentation, pollen size, pollen aperture, thickness of the pollen wall, amount of pollenkitt, pollen hydration status and dominant reserves within the pollen grain, while species within each genus are very similar in most studied characteristics. Most of these features lack relationships to pollinator type, especially in Erythrina and Mucuna. Pollen reserves are discussed on a broad scale, according to the occurrence of protein in the pollen of invertebrate- or vertebrate-pollinated species. Some pollen characteristics are more associated to semi-dry stigma requirements. This apical, compact, cuticularised and secretory stigma occurs in all species investigated. We conclude that data on pollen and stigma structure should be included together with those on floral morphology and pollinator behaviour for the establishment of functional pollination classes.

Pollen morphology of 18 species (32 specimens) representing all three currently recognized sections of the genus Elsholtzia (Elsholtzieae–Lamiaceae) was investigated in detail using light, scanning electron and transmission electron microscopy. Elsholtzia pollen grains are small to medium in size (P=20–50 μm, E=16–45 μm), mostly prolate-spheroidal to prolate, and rarely oblate-spheroidal to subprolate in shape (P/E=0.95–1.46), hexacolpate (the amb more or less circular or ellipsoid) with granular aperture membranes. Three distinct types of sexine ornamentation are observed in Elsholtzia: perforate, rugulose-bireticulate, and bireticulate. The bireticulate pattern is the most common, showing a wide range of morphological variation among species. The exine thickness varies from 1.2 to 2.5 μm. Among the present palynological data, the variability observed in sexine ornamentation of Elsholtzia could be of systematic significance. Current infrageneric classification of the genus Elsholtzia is partially congruent with pollen morphological data.

Pollen morphology of 13 species of the genus Sanguisorba (Rosaceae) was examined by light and scanning electron microscopy. The pollen morphology divided the genus into two main groups: (A) tricolporate with tapered colpus tips, and (B) either tricolporate with opened colpus tip or hexacolporate. The former group was further subdivided into those without vestibulum (A1: S. alpina, S. dodecandra, and S. filiformis) and those with vestibulum (A2: S. agrimonoides, S. ancestroides, S. annua, S. cretica, S. minor, and S. verrucosa), whereas the latter group was subdivided into those with colpus narrow and similar to the A1 type (B1: S. canadensis and S. diandra), those with colpus and mesocolpus somewhat equally wide and forming hexacolporate aperture (B3: S. albiflora, S. armena, S. media, S. menziesii, S. parviflora, S. stipulata, and S. tenuifolia), and those with colpus intermediate between the B1 and B3 types (B2: S. hakusanensis, S. microcephala, S. obtusa, S. officinalis, S. polygama, and S. sitchensis). It is suggested that the A1 type aperture would have evolved to the A2 type as a specialized form and the B types (B1 to B3) in a direction in which the hexacolporate aperture was derived. Implications of pollen morphology for infrageneric classification of Sanguisorba are discussed and the results are compared with molecular phylogenetic studies.

Pollen morphology of 27 species, eight subspecies and one variety of Wendlandia was studied using scanning electron microscopy (SEM). Wendlandia pollen are monads, radiosymmetric, small in size, tricolporate (rarely tetracolporate or bicolporate) and spheroidal (rarely subprolate or suboblate) in equatorial view. The compound aperture consists of ectocolpus, mesoporus and endocolpus. In addition, reticulate sexine and granular nexine were observed. The pollen wall ultrastructure of two Wendlandia spp. was examined by transmission electron microscopy (TEM). The exine consists of the tectum, columellae, foot layer and endexine. The endexine is thickened into a costa around the aperture. The intine forms a protruding oncus at the aperture. The palynological characters show a remarkable uniformity among the Wendlandia spp. Differences with Rondeletia, the main genus of tribe Rondeletieae, exist in the exine pattern, the endoaperture and the pollen wall structure. Our observations indicated that the endoaperture type and the structure of the pollen wall of Wendlandia were similar to those of the Gardenieae–Pavetteae–Coffeeae–Octotropideae clade, which provided palynological evidence for a closer relationship of Wendlandia to subfamily Ixoroideae and the transfer of Wendlandia out of Rondeletieae. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164, 128–141.

Centaurium pulchellum is an annual herb native to Europe, but introduced in South America, where it is widely used in the preparation of digestive infusions and bitter drinks. In this species, a wide variation in the aperture pattern of pollen grains was reported and has been attributed to environmental factors or irregularities at meiosis. For this reason, cytological and palynological studies have been undertaken on two different populations. The pollen grain analysis showed that some types are more frequent within each population, but the most common forms were the typical 3-colporate and 4-colporate. The cytological analysis revealed that the analyzed populations of C. pulchellum have chromosome number 2n = 36. The presence of tetravalents at meiosis strongly suggests that these populations are autotetraploid based on x = 9. The meiotic behavior showed a significant percentage of irregularities in different phases: off-plate bivalents, precocious segregation, laggard chromosomes, bridges, and cytomixis. However these irregularities are not related to the variation in the aperture pattern of pollen grains. The heteromorphism in the pollen grains observed in C. pulchellum could be a normal condition to which the species is well adapted.

The research about palynological study of pollen impacted by the haze of Hibiscus rosa-sinensis from Riau Province and its development as a teaching material for plant anatomy has been conducted in Biology Laboratory of Islamic University of Riau. The objective of this research is to find out of the pollen morphology of H. rosa-sinensis and the result of this study developed for teaching materials for plant anatomy subject. The method is descriptive. The analysis data used descriptive qualitative. The result showed that pollen has several characteristics which can be observed which is impacted by the haze. Pollen was observed is single pollen type, spheroidal sarcoid, polyphenoporate aperture type and exterior ornament. From result of research can be concluded that there is difference of pollen analysis between plant observed. Implication of research results in learning in the form of teaching materials for Plant Anatomy subject. Based on the validation results, it is known that the teaching materials that have been prepared can be used in the learning with percentage level achievement of 90.91% for teaching materials. The subject matter of Plant Anatomy which has been prepared based on the research result can be used in the learning process

Pollen morphology and sporoderm ultrastructure of modern Neurada procumbens L. and Grielum humifusum E.Mey. ex Harv. et Sond. were studied using light (LM) and electron (SEM and TEM) microscopy. Additionally late Holocene pollen of the Grielum -type was studied using LM. Systematic and ecological aspects have been discussed for the family Neuradaceae. The pollen grains of the studied species are characterized by similarities in size, shape, aperture type and differences in exine sculpture (reticulate semitectate exine in Neurada and finely reticulate to foveolate in Grielum ) and sporoderm ultrastructure. The cavea in the exine is situated between the ectexine and endexine which are connected near the aperture region only. A combination of the palynological characters of the Neuradaceae (semitectate exine, rather loose columellae, interrupted foot layer, the cavea in the exine) increases the pollen plasticity, allowing considerable changes of the pollen grain volume but still remains insufficient to survive sharp fluctuations in hydration level.

Determine the morphology structure of pollen on some variation colour of corolla Caesalpinia pulcherrima L. (Swartz) in highland and lowland West Sumatra has been conducted. The result reveals that topography and variation colour of corolla C. pulcherrima L. (Swartz) affects the shape of pollen. Pollen of C. pulcherrima L. (Swartz) has single grains or monad, isopolar polarity, radial symmetry, and size categories large. The length of polar axis (P) 58.16 to 74.11 μm, the length of the equatorial diameter (E) 59.86 to 75.97 μm, so that pollen can be classified into sub-spheroidal sub-oblate, spheriodal sub-spheroidal oblate, and sub-spheroidal prolate. Ornamentation of C. pulcherrima (L.) Swartz was reticulate. The pollen has aperture 3, the type pore and located in equatorial. From these data can be concluded that pollen from varying colour of corolla C. pulcherrima (L.) Swartz has same in terms of unit, polarity, symmetry, size, and type aperture, but it different in terms of shape.

Seven plant species belonging to family Malvaceae were subjected to standard palynological studies in order to generate data for pollen characterization and identification of medicinally important mallows from Punjab, NW India. Pollen grains of this family are unique being porate and echinate having isolated spines. Pollen grains are either 3-porate, 6-7 porate or polypantoporate with oblate spheroidal shape and reticulate or semitectate reticulate exine. Based on various palynological parameters like the range in size, shape, aperture, exine thickness, ornamentation, etc. key to identification of presently studied taxa has been evolved.

The formation of reactive oxygen species in pollen at the early germination stage, which precedes the formation of the pollen tube, was studied. During this period, pollen grain is being hydrated, abruptly increasing its volume, and it passes from the resting state to active metabolism. Fluorescent methods have made it possible to reveal reactive oxygen species in the cytoplasm and inner layer of the pollen wall, intine. The cyto- plasmic reactive oxygen species were mostly found in mitochondria, while extracellular ones were localized in aperture zones of intine, as well as in the solution surrounding pollen grains in vitro. The content of extracellular reactive oxygen species decreased after superoxide dismutase (100 units per ml) and diphenylene iodonium (100 μ M ), which indicates NADPH oxidase as one of possible producent of them. In conditions of suppression of extracellular reactive oxygen species production (100 μ M diphenilene iodonium) or their promoted removal (after addition of 10 to 100 μ M ascorbic acid), the number of germinating pollen grains increased. This effect disappeared after further increase in the concentration of the listed reagents. The result is evidence of the sig- nificance of processes of generation/removal of extracellular reactive oxygen species for pollen germination. DOI: 10.1134/S1062360409060034

Beschorneria yuccoides (Agavaceae) microspores are arranged mostly in planar tetrads. Later on, the pollen grains of the tetrad usually fall apart, but sometimes remain loosely connected by ektexine elements. The ektexine consists of a tectum, of short columellae, and of a thin, discontinuous foot layer. An endexine is absent. The bilayered intine is without any additional thickening that would usually indicate an aperture region. From this point of view the pollen grain might be considered as omniaperturate. The pollen ornamentation is reticulate with wide lumina and robust, smooth muri. The pollen grains show an indistinct sulcus characterised by a loose reticulate ornamentation. The sulcus is not exactly at the distal pole, but shifted towards the equator. No pollen tubes are formed regularly at the sulcus. Instead, pollen tubes are normally formed at the proximal pollen face. The proximal area, indicating a large germination field, is morphologically and functionally clearly an aperture (a ge...

Pollen morphology of 11 species of Murraya and Micromelum (Clauseneae: Rutaceae) was investigated using scanning electron microscopy (SEM) and palynological characters including pollen size, aperture number and exine ornamentation were evaluated. The results indicate that species in M. sect. Bergera and sect. Murraya have very distinct pollen morphology. Species in section Bergera have rugulate to foveolate exine, whereas the tectum in section Murraya is crossstriate. This supports the redefinition of the genus Murraya, retaining only the species of section Murraya, while M. sect. Bergera is better treated as a separate genus. From the palynological point of view, it is suggested that Bergera and Murraya s.s. are not closely related, with the latter being more close to Micromelum and Merrillia, a result in accordance with phytochemical, chromosomal and molecular evidence, thus supporting the reinstatement of the generic name Bergera L. The genus Murraya L. was first published based on a single species, Murraea exotica L., while Bergera L. was based on

The Cycadales are an order of gymnosperms that represent one of the oldest lineages of seed plants. Cycads are thought to have originated in the Carboniferous, and subsequently diversified and geographically expanded throughout the Mesozoic. Despite the geologic diversity of the group, the evolutionary history of cycads remains unresolved. To a large degree this is because the leaves of cycads and various other fossil groups (e.g., pteridosperms and Bennettitales) are morphologically similar. To date there are relatively few fossil cycad reproductive structures. Several are known from the Permian of China, but these compression specimens provide little detailed information useful in tracing the evolution of cycad cone morphology and anatomy. A permineralized cycad pollen cone from the Triassic of Antarctica, Delemaya spinulosa, contains in situ pollen. The objective of the current study is to further elaborate the structure of the pollen grains in this species, with particular emphasis directed at the structure and organization of the pollen wall. The elliptical shape, monosulcate aperture, and small size of the pollen grains are like those of extant Cycadales. The exine, although originally described as homogenous, appears to possess an alveolar organization. Pollen and cone features are compared to those in extant Cycadales.

A study of microsporogenesis (the earliest stage of pollen ontogeny) was undertaken in seven cultivars of Codiaeum variegatum var. pictum, a eudicot species that produces inaperturate pollen grains. Microsporogenesis appears highly variable for the developmental events suspected to be implicated in the determination of aperture pattern. Most eudicots have tri-aperturate pollen grains and microsporogenesis is described as highly conserved in this clade. The observed burst of variation in C. variegatum therefore appears especially remarkable. A plausible hypothesis to explain the variation is that the pollen being inaperturate, the selective forces applying on the ontogeny of the aperture pattern are relaxed.

Taxonomic differences in the needle epidermis characteristics of Pinus sylvestris L. and Pinus uncinata Ramond ex DC. from two Iberian populations were sought; such information could help identify these species when pollen analysis and the inspection of wood anatomy fails. The features of the cuticle are commonly well preserved in the fossil record. Although the epidermal patterns of the examined taxa were similar, qualitative differences were seen in the subsidiary and guard cells. P. sylvestris showed small subsidiary cells homogenously arranged around the opening of the epistomatal chamber, while P. uncinata showed small, lateral subsidiary cells and non-differentiated subsidiary cells in the polar position. The aperture of the epistomatic chamber of P. uncinata was also larger in diameter (15.1 ± 1.8 µm P. sylvestris; 21.1 ± 2.8 µm P. uncinata). Principal components analysis and discriminant analysis was performed on the features of the guard cells characterising the size and shape of the cuticular thickenings — all the variables analysed can be measured in disperse stomata in microscope preparations for pollen analysis. Significant differences were found in the upper woody lamellae width and the coefficient associated with the shape of the medial lamellae borders (discriminant analysis weighting 0.739 and 0.826 respectively). Other significant parameters included the coefficient associated with the relative size of the medial lamellae border width of the guard cells with respect to the distance between the external limits of the medial lamellae borders, and the length of the upper woody lamella. Different light regimens appeared not to significantly affect the variability of the studied features.

Morphology and ultrastructure of pollen grain were described for six cornelian cherry (Cornus mas L.) cultivars (Degirmendere, Erkenci Degirmendere, Iri Bardak, Yuvarlak Bardak, Uzun Memeli, and Bugur) using light microscopy and both scanning and transmission electron microscopy. Pollen grains of cornelian cherry cultivars are trizonocolporate, the germinal furrow extending almost the full length of the grain axis. Pollen grain length for the studied cultivars ranged from 23.63 to 25.13 mu m. Two different pollen shapes were observed: oblate spheroidal and prolate spheroidal. Significant changes in various layers of the pollen wall are as follows: the thickness of the intine: 233.1 to 406.4 nm, exine: 510.2 to 842.7 nm, and total wall 851.4 to 1175.8 nm. Percentages of abnormal pollen grains ranged from 3.9% to 27.6% among the cultivars. Abnormal pollen grains were categorized as: 1) shrunken pollen grains of abnormal appearance with little cytoplasm; 2) pollen grains of normal appearance with little or no cytoplasm; and 3) shrunken, abnormal pollen grains of elliptical shape with a colpate-type aperture. Australian Marine Science and Technologies Committee Australian Research Council

O trabalho trata da morfologia polínica e de descrições taxonômicas de 12 espécies de Asteraceae correspondentes em 12 diferentes gêneros, distribuídos em nove tribos. Todas as espécies estudadas são utilizadas como medicamentos pelos moradores da Vila Dois Rios, Ilha Grande, Angra dos Reis, Rio de Janeiro. Neste estudo objetivou-se caracterizar os tipos polínicos das espécies usadas por esta comunidade e fornecer chaves diagnósticas de caracteres macromorfológicos e micromorfológicos que auxiliem a identificação das mesmas. A identificação taxonômica e palinológica correta é pré-requisito para estudos que validem a eficácia e segurança terapêutica dessas espécies. Deve-se considerar, ainda, que a utilização desses conhecimentos é importante para a comunidade, como por exemplo, na melissopalinologia. Os grãos de pólen foram acetolisados, medidos, descritos e ilustrados sob microscopia de luz. Para observar detalhes da superfície e abertura, grãos de pólen não acetolisados foram analisados em microscópio eletrônico de varredura. Foram estudadas as características dos grãos de pólen como forma, tamanho, constituição da sexina e abertura. Os resultados mostraram que a morfologia polínica é bem definida entre as espécies estudadas, podendo ser usada para sua identificação e sustenta o caráter euripalinológico de Asteraceae.

Floral diversification in the genus Pedicularis (Orobanchaceae) is remarkable among flowering plants. In this genus, floral morphology and pollinator behavior are closely co-adaptive. In the current paper, pollen grains of 23 representative species of Pedicularis mainly from North America, with two species from Japan and two species from China, whose pollination ecology was previously studied, were examined using light microscopy and scanning electron microscopy. Two pollen aperture types and three kinds of exine ornamentation were recognized among these species. In addition, pollen data from previous and the current studies of Pedicularis were integrated and analyzed, together with some pollination characters. There was a significant association between pollen aperture types and corolla types, as well as between pollination syndromes and corolla types. However, there was no association of exine ornamentations with corolla types. The relationships and evolution of this genus were discussed with regards to pollen morphology, corolla types and pollination syndromes.

Pollen of 12 species of the genus Spirea L. growing in different regions of Siberia and the Far East was investigated. The ultrasculpture of pollen grains is described. On the basis of aperture morphology and exine sculpture, pollen grains are typified, with key indices given for their identification. The species of the Spiraria section are distinguished by large grains. Pollen grains of S. media and S. alpina considerably vary in size. The level of natural polymorphism of palynological indices has been established.

Pollen grains of 17 taxa (14 species with two additional subspecies and one variety) of genera Patrinia Juss. and Nardostachys DC. in tribe Patrinieae (Valerianaceae) were studied using light microscope, scanning electron microscope, and transmission electron microscope. Pollen grains are medium (37.41 × 43.60 ㎛ - 45.65× 48.50 ㎛) to large (54.88 × 59.41 ㎛ - 61.70 × 71.00 ㎛) in size, tricolpate (rarely tetracolpate) with the characteristic halo surrounding the aperture. In equatorial view, the pollen is oblate to subprolate, and in polar view, it is mostly circular or rarely 3-lobed. Two major pollen types are recognized on the basis of exine sculpturing patterns; Type I: Exine is composed of echinae together with sparse or dense microechinae, and verrucae shallow or rarely absent (Nardostachys and sections Paleopatrinia, and Monanadropatrinia of Patirinia). - Type II: Exine is composed of massive echinae together with dense microechinae, and prominent verrucae (section Centrotrinia of Patrinia). In TEM sections, columellae are extended from the footlayer into verrucae, and exine thickness is uniform at the pole and equator. Additionally, the infrageneric classification systems of the Patrinieae were evaluated on the basis of the present data.

The small aquatic family Hydatellaceae was recently assigned to the early‐divergent angiosperm order Nymphaeales. Pollen morphology is described using both SEM and LM for all 12 species of Hydatellaceae, and using TEM for one species (T. submersa). These observations are compared with pollen data from the other two families of Nymphaeales, Nymphaeaceae and Cabombaceae, including original observations for both genera of Cabombaceae. No significant interspecific variation in pollen morphology occurs in Hydatellaceae, though both of the perennial species (Trithuria inconspicua and T. filamentosa), which could be apomictic, possess at least partially sterile and collapsed pollen. Pollen of Trithuria is small, oblong or rounded (viewed from the distal pole) and monosulcate. The aperture has a distinct margin and extends the full length of the pollen grain. The exine is tectate‐columellate. The tectum is perforate: discontinuous with numerous small perforations randomly scattered over the entire non‐apertural s...

The pollen morphology and ultrastructure of 20 species, representing eight genera of the Magnoliaceae are described based on observations with light, scanning and transmission electron microscopy. The family represents a homogeneous group from a pollen morphological point of view. The pollen grains are boat-shaped with a single elongate aperture on the distal face. The tectum is usually microperforate, rarely slightly or coarsely rugulose. Columellae are often irregular, but well-developed columellae do occur in some taxa. The endexine is distinct in 14 species, but difficult to discern in the genera Parakmeria, Kmeria and Tsoongiodendron. Within the aperture zone the exine elements are reduced to a thin foot layer. The intine has three layers with many vesicular-fibrillar components and tubular extensions in intine 1. The symmetry of the pollen grains, shape, type of aperture and ultrastructure of the intine show a remarkable uniformity in the family. Nevertheless there is variety in pollen size, ornamentation and the ultrastructure of the exine. The pollen of Magnoliaceae is an example of an early trend of specialization, and supports the view that Magnoliaceae are not one of the earliest lines in the phylogeny of flowering plants.