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The pistil in the flowers of the Iphigenieae (Camptorrhiza, Iphigenia, Omithoglossum) is usually tricarpellate. The carpels are coherent generally, with closed sutures and seemingly bitegmic ovules.Camptorrhiza differs from the others in having a single compound style. The pistils of most species of these genera have a common vascular structure: three dorsal bundles which run into the style(s), a number of lateral bundles, six placental bundles, and up to three compound septal bundles. The latter nine bundles usually differentiate from a central vascular plexus above the base of the locules. There may be fewer than three septal bundles in some specieS. When present, the septal bundles usually die out in the ovuliferous region, but in some cases they persist to the apex of the locules.

Summary Deposition of the secondary wall in the palisade cells of the testa of lima bean seeds appears to involve the endoplasmic reticulum primarily. Although the principal component of that wall is highly oriented and highly crystalline cellulose, virtually no microtubules appeared during cell growth and maturation. Some indications were found that ribosome aggregation in the cytoplasm was associated with the origin of lamellae of the endoplasmic reticulum. Ribosome-like bodies were also prominent at the plasmalemma during formation of the secondary wall.

Tepallary and staminal vascularization in a random sample of the Wurmbaeoideae was eomprised of three vascular bundles per tepal and one per stamen, as in the Rosaceae. The structural similarity of the vascularization of the carpel of the Wurmbaeoideae with that of the Rosaceae is mentioned with the tentative implication of a common ancestry.

Most Helonieae have only slight septal indentations between the three carpels: in Xerophyllum deep septal clefts extend centripetally and completely enclosed, narrow septal pockets occur in Metanarthecium. Other unique generic features are found: tepallary-staminal nectarial glands in Heloniopsis, zygomorphy in Chionographis, and dioecism in Chamaelirium. The carpels are biovulate in Chionographis; there are two to several ovules per carpel in Xerophyllum; 8–12 ovules occur in the carpel of Chamaelirium; and numerous bitegmic ovules are borne in many longitudinal rows on enlarged placentae in Helonias, Heloniopsis, Metanarthecium, and Ypsilandra. Except for Metanarthecium, this last-named group of genera displays a near ring composed of ‘accessory’ placental bundles and a compound septal bundle (with normally oriented xylem and phloem) in cross-section at the inner edge of each septum. Ventral bundles occur in the other four genera.

The Tofieldieae consist of Narlhecium, Nietneria, Pleea, and Tofieldia. Although the three carpels of the pistil are generally coherent, their bases are separate for a short distance in some species of Tofieldia and in Pleea, where a septal nectary seems to be differentiated. These two genera are also alike in the extension of the chalaza as a filiform hook. The sutures are open at flowering only in some species of Tofieldia. Nietneria is distinguished by its inferior ovary and the alternate structure of the pistil. No raphide idioblasts were found in the carpels of any species.

Sweet potato (var. Jersey) and yam (var. Velvet) are ‘mealy’ and ‘soggy’ varieties, respectively, of Ipomoea batatas Poir. In the raw state the storage roots of both have virtually the same histological structure: more or less abundant starch grains in the parenchyma cells and few intercellular spaces. After baking, the sweet potato shows rounded cells which are full of gelatinised starch and are separated by numerous small, capillary-like intercellular spaces. The baked yam has very little starch, shrivelled cells, ruptured and shrunken cell walls and many large intercellular cavities. The relationships of histological structure to textural properties in these roots and in the mealy and soggy varieties of the tuber of the Irish potato are discussed.

“Sweet potato” (var. Jersey) and “Yam” (var. Garnet) are mealy (dry) and soggy (moist) varieties, respectively, of Ipomoea batatas Poir. (Convolvulaceae). The raw fleshy roots of both varieties have essentially similar quantities of all measured variables except for cellulose, hemicelluloses, and amylose. On baking, only the amounts of non-reducing sugars and possibly cellulose appear unchanged, while the reducing sugars increase markedly in both varieties, with those of the yam far exceeding those of the sweet potato. The yam's starch content (particularly the amylose fraction) falls faster and to a lower level; its water-soluble pectin content increases; and its hemicellulose content is particularly decreased. Scanning electron microscopy (SEM) showed that the cell walls of the raw fleshy roots of both varieties are coated with long parallel fibrils, 0.25–1.5 μm in diameter, which appear to be hemicellulosic. Veranderungen in der Starke und anderen Kohlenhydraten beim Verbacken von Impomoea batatas. Suskartoffeln (Var. Jersey) und Yamswurzel (Var. Garnet) sind mehlige (trockene) bzw. teigige (feuchte) Varietaten von Ipomoea batatas Poir. (Convolvulaceae). Die rohen fleischigen Wurzeln beider Arten enthalten, mit Ausnahme der fur Cellulose, Hemicellulosen und Amylose gefundenen Werte, im wesentlichen gleiche Mengen an allen ubrigen ermittelten Variablen. Beim Verbacken bleiben in beiden Arten lediglich die Mengen an nicht-reduzierenden Zuckern und moglicherweise an Cellulose unverandert, wahrend die reduzierenden Zucker merklich zunehmen, wobei die Werte bei Yam diejenigen bei der Suskartoffel erheblich ubertreffen. Der Starkegehalt bei Yam (insbesondere die Amylose-Fraktion) nimmt schneller und bis zu einem niedrigeren Gehalt ab; der Gehalt an wasserloslichem Pektin nimmt zu; der Gehalt an Hemicellulosen fallt besonders stark ab. Rasterelektronenmikroskopische Untersuchungen zeigten, das die Zellwande der rohen fleischigen Wurzeln beider Varietaten von langen parallelen Fibrillen von 0,25–1,5 μm Durchmesser, vermutlich hemicelluloseartiger Natur, uberzogen sind.

A survey of species of the prunoid genera, Maddenia and Pygeum, and of the genus Osmaronia has been made. The ovules of all are pendent, campylotropous, and epitropic. In the prunoids, the ovular supply is intimately connected with a central vascular plexus in the base of the carpel; that plexus is absent from Osmaronia. The prunoid carpels are marked by an extensive degree of fusion among the ovular and wing bundles, by fusion of the sutural margins, by fusion of the 2 integuments of the ovule to a single massive one, and by the presence of 3 or 5 well-developed bundles in the base. The carpel of Osmaronia also has a strongly fused bipartite ovular supply, separate bundles of which, however, become very much attenuated before reaching the funiculus; it has independent ovular and wing bundles, completely separate carpellary margins, 2 clearly separate integuments in the ovule, and 6 distinctive bundles in the carpel base. At the funiculus, the wing bundle of Osmaronia is connected with the adjoining weak ovular bundle by a welldeveloped vascular branch. Various particularities in the morphology of Osmaronia lend support to its segregation into a unique tribe, the Osmaronieae of Rydberg. IN CONCLUDING the comparative study of the prunoid carpel (Sterling, 1964), the author has now examined the young carpels of the 3 remaining genera commonly placed in the Prunoideae: Maddenia, Pygeurn, and Osmaronia. It should be noted that Rydberg (1918) removed Osmaronia to the separate tribe, Osmaronieae. The results of the present investigation indicate that such a segregation is justified. However, Osmaronia has been examined in this portion of the study as a concession to other taxonomic opinions, such as that of Focke (1894). A recent study (Sterling, 1963) has already shown that Prinsepia cannot be regarded as a prunoid genus. MATERIALS AND METHODS-The sources of the floral specimens were the herbaria of the University of California at Berkeley and Davis, respectively, and the herbarium of the Royal Botanic Gardens at Kew. The species used were: Maddenia himalaica Hook. f. & Thomas; M. hypoleuca Koehne; M. hypoxantha Koehne; and M. wilsonii Koehne; Pygeum fragrans Merr.; P. glandulosum Merr.; P. megaphyllum Merr.; P. preslii Merr.; P. topengii Merr.; and P. vulgare Merr.; Osmaronia cerasiformis (T. & G.) Greene. As far as possible, flowers were taken at the same stage of development, namely, unfolding of the petals. The methods of specimen preparation have been described earlier (Sterling, 1964). RESULTS-Maddenia-According to Focke (1894), the genus is dioecious, and the pistillate flowers are bicarpellate. However, Koehne (1911) found that in the Chinese species, at least, the I Received for publication July 19, 1963. This investigation was aided by funds from the National Science Foundation, given under grant G-16142. The microtechnical work was performed by Dr. Maxine Thompson. It is a pleasure to thank both the Foundation and Dr. Thompson for their help. flowers are perfect and monocarpellate. The writer has examined all the specimens of Maddenia in the herbaria of the University of California at Berkeley and the Royal Botanic Gardens at Kew, with the same results: all species, including M. himalaica, have perfect flowers that are predominantly monocarpellate. Each carpel has 2 monotegmic ovules which are pendent, campylotropous, and epitropic. The carpellary margins are fused throughout the length of the ovary. Although the commissural suture is marked externally by a slight cleft along the ventral surface of the ovary, internally the ventral ovarian surface is smooth from the base of the locule up to the level of ovular attachment. Upwards from this level to the top of the locule, a linear groove is evident on the internal ventral surface. (This groove is fairly deep in M. hypoleuca.) A short distance above the insertion of the staminal traces, the center of the vascular cylinder is occupied by a sparse vascular plexus (Fig. 1, 2). At flowering, that plexus is still procambial. The vascular cylinder that supplies the carpel may be composed of 5 main bundles (M. himalaica, M. hypoleuca), or only of 3 large bundles (M. hypoxantha, M. wilsonii). When 5 bundles are present they are the dorsal bundle, 2 wing bundles, and 2 inner vegetative bundles next to the ovular supply.2 The bipartite ovular supply lies between the wing bundles, close to the sagittal plane. Xylem and phloem in the dorsal, wing, and inner vegetative bundles are radially collateral. However, in the ovular supply the xylem and phloem are almost tangentially collateral at the sagittal plane, with the phloem of each half directed toward the phloem of the other. These phloic 2The terminology used here has been explained by Sterling (1964).

The carpels of 2 groups of pomoid genera, Amelanchier, Malacomeles, Peraphyllum and Aronia, Malus, Pyrus, and Sorbus, were analyzed morphologically. Open sutures are associated with a lesser extent of tegumentary fusion and ovular bundle-wing bundle fusion than are closed sutures. However, in the genera as a whole (and particularly in Aronia and Sorbus), the extent of sutural closure is inversely related with the amount of intercarpellary adhesion and with the fusion of carpels to the floral cup. In the Amelanchier group and in Malus and Pyrus, ovularand wingbundle fusion is directly related with intercarpellary adhesion. Malus and Pyrus have closer structural resemblances with one another than they have with Aronia and Sorbus.

DESPITE THE great wealth of botanical literature concerned with the initiation of adventitious buds (Priestley and Swingle, 1929; Buvat, 1944-45; Peeters, 1947), there have been relatively few anatomical studies on bud initiation in tissues cultured in synthetic media. Buvat (1944-45) has summarized these and has, himself, added considerably to an understanding of the problem of "dedifferentiation"2 of plant cells. However, his investigations concern principally the cytological aspects of primordium formation. Although Camus (1949) has studied the changes in subjacent tissues during bud development, he has not considered the details of initiation of the shoot primordia. Previous communications (Skoog, 1944; Skoog and Tsui, 1948, 1951; Sterling, 1950) have shown a marked correlation between relatively high levels of adenine, supplied through a culture medium, and bud initiation in tobacco stem segments. Obviously, the establishment of such a relationship makes possible the chemical control of bud formation. It is, therefore, of interest to place on record the successive steps in this controlled initiation of shoot primordia in vitro. This paper presents an anatomical description of such development and considers the latter in relation to the general problems of meristematic activity and dedifferentiation. MATERIALS AND METHODS.-The materials and methods used are those reported earlier (Sterling, 1950), with the limitation that this account deals only with the tobacco stem segments which received adenine sulfate (40 mg./l.) in the basal medium. The material is representative of the samples used in physiological studies on growth and tissue composition. Segments grown on control media were described in the earlier paper. SITES OF BUD ORIGIN.-In these cultures, there are three maj or regions of bud formation, Viz., cambium-external phloem, internal phloem, and callus. The region of the cambium and its young phloic derivatives produces the maj ority of bud primordia. In most instances, no sharp distinction can be made between these two classes of cells in the rapidly dividing cambial zone; therefore, this source of buds was previously reported as cambial (Sterling, 1950). However, in some cases bud primordia are found exclusively in the external phloem, with differentiated sieve tubes lying be

The two genera of Buxbaum's tribe Wurmbaeae, Anguillaria and Wurmbea, have multiovulate carpels. There are deep septal indentations between the carpels of Anguillaria, but the wings of adjoining carpels are fused to solid septa in most species of Wurmbea. In Anguillaria the carpels have open sutures or prominent commissural markings; in Wurmbea the carpels generally lack these characteristics, and some species have a vascularized, columella-like axis in the centre of the pistil. In both genera there are a dorsal bundle, lateral bundles, and two placental bundles in each carpel. At the inner edge of the septum there are one or two septal bundles in Anguillaria and one or none in Wurmbea. The ovules are monotegmic, the integument and funiculus being partly fused in Anguillaria and mostly fused in Wurmbea. An obturator is present in Anguillaria but absent from most species of Wurmbea.

SUMMARY The submicroscopic structure of the starch grains of Zea mays and Triticum sativum was studied electron-optically from replicas made of internal, fracture surfaces. In corn starch, long cylindrical microfibrils were found, arranged in a radial direction and imbedded in an amorphous matrix. Their diameter was uniformly about 200 A. Microfibrils were also indicated in wheat starch because of the prominence of their ends in surface view. Many microfibrils in corn starch appeared to be helically coiled. The more ordered starch substance was presumed to be localized principally in the microfibrils.

The pistil of Androcymbium closely resembles that of Colchicum: it is tricarpellate usually, syncarpous and multiovulate, and the carpels of most species have open sutures and bitegmic ovules. The only species with closed carpellary sutures, A. dregei has monotegmic ovules. There are always three dorsal bundles and three compound septal bundles, which latter may bifurcate into simple septal bundles. Six placental bundles (two per carpel) are differentiated, either separately from the compound septal bundles or as lateral branches of them. A statistical evaluation of 47 species (6 genera) of the hemisyncarpous Wurmbaeoideae shows a significant tendency for bitegmic ovules and two simple septal bundles per septum to be associated with open sutures and for monotegmic ovules and no septal bundles to be associated with closed sutures.

The multi-ovulate pomoids, Chaenomeles, Cydonia, and Docynia, all have closed sutures and extensive fusion between carpel and floral cup and between ovular and wing bundles. Although the ovules in Docynia are generally apotropic and few in number (4-7), the ovules in the other two genera are pleurotropic and numerous (15-48). A statistical treatment of the whole tribe of Pomoideae shows that in carpels with open sutures ovular and wing bundles definitely tend to be separate while in those with closed sutures these bundles tend to be fused. To a lesser degree carpels with open sutures also tend to have bitegmic ovules, separate carpels, and a lesser extent of fusion between carpel and floral cup, while carpels with closed sutures tend to have monotegmic ovules, united carpels, and a greater extent of fusion between carpel and floral cup. THE POMOID genera, Chaenomeles, Cydonia, and Docynia, have multi-ovulate carpels. In 1906 Schneider described the genus Pseudocydonia. Weber (1964) believed, however, that this taxon is really Cydonia and that Pseudocydonia sinensis Schneid. is more properly named Cydonia sinensis (Dum.-Cours.) Thouin. If it be considered that the multi-ovulate condition is atavistic (Bailey and Swamy, 1951; Eames, 1961), the carpels in this group could be expected to show other primitive features. It is with considerable interest, then, that an analysis of the multi-ovulate genera has been undertaken. MATERIALS AND METHODS-Flowers for this study were generously provided by the Miorris Arboretum, the Arnold Arboretum, the U. S. National Herbarium, the Harvard University Herbarium, and the herbaria of the Natural History Museum of Vienna, the University of Vienna, and the University of California (Davis, Berkeley). The species studied, with the number of samples indicated in parentheses, incluide Chaenomeles cathayensis (Hemsl.) Rehd. (1), C. japonica (Thunb.) Lindl. (3), C. speciosa (Sweet) Nakai [C. lagenaria (Loisel) Koidzuml (2); Cydonia japonica Lindl. (2), C. oblonga Mill. (2), C. sinensis (Dum.-Cours.) Thouin (6), C. vularis Pers. (4); Docynia delavayi Schneid. (2), D. docynoides (Schneid.) Rehd. (2), D. indica Decne. (2), D. rufifolia (Ldveill6) Rehd. (1). Specimens were prepared in the manner previously described (Sterling, 1964a). As in previous studies (see Sterling, 1964c) the observer follows the course of the vascular bundles, as they appear to ascend from the receptacle. No ontogenetic movements are implied in the de'Received for-publication February 9, 1965. This study wasi supported by grant G-16142 fr om the National Science Foundation and by a fellowship grant t_ _-,_h Tr_hr_ CMna_ 17_1-___1nhoim V_-_AlW ilfSi.ir4scriptive terminology, which has been chosen mainly for convenience. RESULTS-Chaenomeles-A set of dorsal collateral bundles, equal in number to the number of carpels (4-5), is separated from the gynoecial cylinder in the receptacle. The remaining bundles of the cylinder, which are normally oriented, lie grouped closely together in a like number of arcs. These arcs are convex centripetally at the base of the locules and alternate with the locules and the dorsal bundles (Fig. 1). The arcs become Vshaped higher up, with the vertices directed centripetally. Each divides radially at the vertex of the V. The division takes place just below the locule in C. cathayensis and above the locular base but below the lowermost insertion region in the other two species. Two large ventral bundles are thus formed, each supplying one of two adjoining carpels above and furnishing branches to the ovules. With reference to the receptacle, the ventral bundle has centripetal xylem and centrifugal phloem when first delimited. Below the lowermost insertion region in C. cathayensis, but above this region in the other two species, the ventral bundle rotates and becomes V-shaped with the vertex centripetal. It then divides radially into a wing bundle that lies near the carpel margin and a large ovular bundle complex near the suture (Fig. 3). These bundle groups are oriented so that the median longitudinal planes of the two derivatives are near-tangential, the phloem of the wing bundle facing the lateral carpellary margin and the phloem of the ovular bundle complex facing the suture. The ovu]ar bundle complex consists of two or three nearly distinct bundles, the innermost one (i.e., closest to the funiculi) giving rise to a branch to each ovule along a carpellary margin. Along its upper course the ovular bundle complex becomes more and more attenuated. It disannears

A B S T R A C T A comparative study of carpellary structure in the spiraeoid subtribes Quillajeae and Sorbarieae has shown that morphological inter-relationships are similar to those of other Rosaceae. When the suture is closed the carpels tend to be coherent and the ovular and wing bundles tend to be fused. These relationships are statistically significant in the Spiraeo deae as a whole. The construction of the gynoecium in Lindleya and in most species of Vauquelinia resembles that of a pomoid. Other features of a pomoid-spiraeoid affinity have been discussed. sub-tribes of the Spiraeoideae: Holodisceae, Neillieae, Spiraeeae, and Ulmarieae. The present study deals with the two remaining sub-tribes of this group: Quillajeae and Sorbarieae. Both Maximowicz (1879) and Jue (1918) regarded the Quillajeae as the most primitive sub-tribe of the Spiraeoideae. On the basis of the vascular structure of the pedicels and carpels, Bonne (1928) agreed with this view and declared that the other groups in the Rosaceae could be considered to diverge from the

This preliminary study has related the nature of rupture in starch grains, induced by ultrasound, to the ambient atmosphere, the concentration of the suspension, the frequency and the time of irradiation. It has been tentatively concluded that principally mechanical effects have been induced under conditions that would promote vaporous cavitation (280 KHz, 15 W/cm2). In an atmosphere of hydrogen, many deep conical pits are produced. In an atmosphere of air or oxygen, deep pitting is somewhat less pronounced than in hydrogen but injury to other parts of the surface is greater. Virtually no effect is produced in vacuo, and under carbon dioxide the effect is very weak. The extent of damage increases with time of radiation and decreases with increasing concentration of starch in the suspension. It is suggested that damage produced by ultrasound indicates a primarily radial structure of submicroscopic units in the starch grain. Explanations proposed for the effects observed must be tested in further experiments.

Elongated acicular and tabular crystals have been found in the laticiferous cells ofAllium cepa (var. “Yellow Globe”). Although these show predominantly lipoidal properties, a possible proteinaceous relationship has been discussed.

A B S T R A C T The structure and distribution of laticifers has been studied in the bulb scales of 52 species and varieties of Allium. Differences in laticifer position, shape, and pitting in the cross wall of the observed specimens support Traub's separation of the subgenera Amerallium and Allium within the genus Allium. If the species examined are representative, anatomical evidence also justifies the distinction of the section Melanocrommyum and the subsection Cepa. THE CLASSIFICATION and interpretation of the genus Allium and its relatives has been a particularly difhcult problem in systematic botany. A llium has been placed in the tribe Scilleae of the Liliaceae (Lindley, 1853); in the tribe Allioideae, subtribe Allieae, of the Liliaceae (Krause, 1930); and in the tribe Allieae of the Amaryllidaceae (Hutchinson, 1934). Within the genus Allium there have also been variations in conceptual treatment. On morphological grounds different sectional groupings were made successively by Don (1827), Regel (1875), Vvedensky (1946), and Stearn (1946a). With the continuing discovery of many New World species and the accumulation of data on cytology and leaf anatomy (Feinbrun-Dothan, 1954; Traub, 1968a), Traub (1968b) modified Stearn's (1946a) classification somewhat and erected subgenera, putting all the New World species and some Old World ones in one subgenus, Amerallium, and most of the remaining Old World species in the

Native and Lintnerized potato starch grains were freeze-fractured and freezeetched. All samples showed a granular surface. The Lintnerized samples, in addition, presented unique structures which have been described as microfibrils. The question, whether the granules and the microfibrils seen here are real structures in the starch grain or artifacts produced by the freeze-etch technique is discussed.

SUMMARY Apple tissue was frozen at different temperatures and in different solutions, thawed, examined microscopically and tested for resistance to compression (firmness). In slow freezing, ice crystals separated the cells, crushed them, and ruptured ceil walls to produce radial splits in the tissue. The mechanical freezing damage occurs during freezing rather than during thawing. The firmness of frozen tissue was much lower than that of raw tissue. The effect of most added solutes was to minimize ice-caused damage and to increase firmness with increasing concentration. The lower the temperature of freezing, the firmer was the tissue and the less was the amount of tissue disruption. The maximum firmness of frozen tissue was about half that of raw tissue, with the major decrease in strength due to loss of turgor. Firmness was increased to about twice that of raw tissue by immersion of the raw tissue in salt solutions at -2°C or at lower temperatures if the solutions remained unfrozen.

THE INVESTIGATIONS of Foster (1944, 1945) aiid Bloch (1946) have indicated some of the major problems concerned in sclereid ontogeny. The intermittent differentiation of isolated idioblasts, which is characteristic of many plant organs, raises questions inot only in the field of histogenesis, but also properly in the realm of physiology. In the course of an investigation on shoot organization in Douglas fir (Sterling, 1946), the writer was able to observe the program of development of the nimerous sclereids which appear in the pith and cortex of that plant. The present study was undertaken to ascertain the details of sclereid ontogeny in a member of the Coniferales. Sclereids have been reported in the vegetative organs of various genera of conifers. Among the Pinaceae, they are noted as occurring in the leaves and shoot of Pseudotsuga (Allen, 1945), in the pith of Picea (Lewis and Dowding, 1924) and Cedrus (Bertrand, 1874), in the cortex of Cedrus and Larix (Neger and Kupka, 1920), in the cortex (L,ewis and Dowding, 1924) and pith (Busse, 1893) of Abies, and in the root and shoot of Keteleeria (Pirotta, 1890). None have been reported from the Cupressaceae, except as noted in Feustel's (1921) review of certain dissertations inaccessible to the writer. Bailey and Faull (1934) mention their occurrence in the old pith of Sequoia sempervirens. Of the other taxodes, sclereids have been found only in Sciadopitys (Chamberlain, 1935; Miahlert, 1885; Mohl, 1871; Solms-Laubach, 1871; and Thomas, 1865) and Cunninghamia (TThomas, 1865). In the Taxaceae, sclereids have been found in both Cephalotaxus (Bertrand, 1874; Rothert, 1899; Thomas, 1465) and Torreya (Bertrand, 1874) but not in Taxus. Acmopyle (Sahni, 1920), Phyllocladus (Bertrand, 1874), Podocarpus (Brooks and Stiles, 1910; Orr, 1944; Puchinger, 1923; Thomas, 1865), and Saxegothaea (Tison, 1909) of the Podocarpaceae are mentioned in the literature as possessing sclereids. Both Araucaria (Lopriore, 1905; Mahlert, 1885; Seward and Ford, 1906) and Agathis (Bertrand, 1874; Mohl, 1871; Puchinger, 1923; Solms-Laubach, 1871; Thibout, 1896; Thomas, 1865) have often been reported to have these elements, in their vegetative, as well as reproductive, organs. MtATERIALS AND METHODS.-The methods of investigation have been outlined in the writer's abovementioned paper. Although most of the material studied was sectioned, some shoots were mnacerated in Jeffrev's solution (Sass, 1940). The macerated material was then dehydrated in a solution of glycerine to which phloxine had been added, cleared. and mounted in Canada balsam. This technique was not adequate to delineate the cell walls sharply: Received for publication August 31, 1946. phloxine appears to be principally a protoplasmic stain, and the refractive index of the balsam is quite close to that of the lignified sclereid wall. The writer would recommend the use of a specific lignin stain and mounting in a medium with a low refractive index. Drawings for the present paper were made by camera lucida. SCLEREID ORIGIN AND DISTRIBUTION.-During the initial period of bud elongation, from February to Marclh, sclereids are absent from the tissues of the young slhoot. They appear first at the time of initial transverse expansion of the pith, which coincides with the formeation of cataphylls (Sterling, 1946). The sclereids are first noticeable among the elongated pith cells just below the developing zone of transverse expansion. They appear in the cortex only about the end of bud scale deposition, wlhen the cells furnished by the receptacular meristein (Korody, 1937; Sterling, 1946) begin to elongate markedly and raise the bud scales. The sclereids arise at this time among the elongating cells produced by this meristem in the cortex. Immediately after their first appearance in the regions noted above, isolated idioblasts can be seen developing much farther down in the shoot, in a very scattered distribution. These occur in both pith and cortex. Throughout the development of the new bud (while the pith expands and while the cell rows of the "receptacle" elongate in the cortex), new sclereids are formed continually amonag the older ones, increasing the density of their concentration. Although the sclereids of Douglas fir are especially abundant just below the area of transverse expansion in the pith, many are found in the cortex as well as the "medullary ray" areas between the vascular bundles at this level. According to Allen (1915) they also occur in the leaves and scattered throughout the rest of the shoot. Nowhere, however, are they present in as dense a concentration as in the regions of their first appearance. SCLEREID ARRANGEMENT.-In general, the sclereids of Pseudotsuga are isolated and randomlv distributed. No precise relationship to specific series of mother cells or position in a file of cells or relationship to specific divisions in a file could be ascertained, as in Monstera (Bloch, 1946). However, in the pith certain patterns of distribution recur occasionally which may be worthy of note. In many instances, two superposed cells of the medullary rib meristem will differentiate simultaneouslv to branehed sclereids, as shown in fig. 2. In one apex, several of these coupled superposed idioblasts occurred in the same vertical cell file, with undifferentiated parenchyma between the groups (as observed occasionally by Bloch, 1946). Likewise, a juxtaposed situation of the sclereids is sometimes encountered, as in fig. 9. In an older pith, there umay also be indiscriminately associated groups of three

The carpels in Crataegus, Hesperomeles, Mespilus, and Osteomeles appear to constitute a morphologically related group: all have bony pits, ovules that tend to be acollateral (usually superposed), and clearly separate ovular and wing bundles, i.e., no "ventral" bundles, at the level of ovular insertion. In species whose carpels have no sutural opening, the integuiments are more extensively fused with one another, the degree of intercarpellary fusion tends to be greater, and the carpels are fused with the floral cup to relatively higher levels than in those species whose carpels have a sutural opening. In the few cases in which wing and ovular bundles are adnate at the locular base (Crataegus monogyna, Mespilus, Osteomeles anthyllidifolia, 0. schwerinae), the extent of interand extracarpellary fusion and sutural closure is among the most advanced. THE PRESENT study initiates an analysis of carpel morphology in the rosacean tribe, Pomoideae. In earlier investigations (Sterling, 1964a, 1964b), the structure of the prulnoid carpel was considered, with the resulting documentation of 4 prinicipal phylogenetic trenids: (1) complete fusion of 2 integuments to a single massive one; (2) reduction in the number of vascular bundles in the base of the carpel; (3) reduction in prominence of the ovular bundles; and (4) progressive acropetal fusion of the ovular bundles with one another and with the wing bundles. These trends accompany the progressive closure of the carpellary suture, anl event that was choseni on a priori grounds as a primiary evolutionary development. The miiembers of the Pomoideae appear to constitute a closely related group. They share a commoln polyploid base number of 17 (Moffett, 1931), occasionally 16 (Sax, 1931). Intergeneric hydrids are well known (Sax, 1931, 1933; Ferniald, 1947). The fruit is almost invariably a pome. In all but the miulti-ovulate genera, the ovules are erect, anatropous, and apotropic (i.e., their funiiculi are ascending, their chalazae are directed away from-l the placenta, and their micropyles face the base of the locule). One the basis of the histology of the pit of the mature fruit, i.e., whether that structure is cartilaginous or osseous, Lindley (1822) divided the pomoid geniera into 2 primary groups. The same major classification has been followed by Pechoutre (1902) and Rehder (1947). Although other investigators (Decaisne, 1874; Focke, 1894) have used different features for a primary differentiation, the grouping of Linidley will be followed I Received for publication December 21, 1963. This study was aided by grant G-16142 from the National Science Foundation and by a Fellowship grant from the John Simon Guggenheim Memorial Foundation. Dr. Maxine Thompson prepared many of the slides used in this research. in this study because it appears to be in accord with other morphological evidence. Among the Pomoideae with "bony" carpels, the genera Crataegus, Hesperomeles, Mespilus, and Osteomeles seem to share a common carpellary construction. (Indeed, Mespilus and Crataegus are frequenitly regarded as being closely related on other grounds.) Consequently, it seems reasonable to examine their carpels for indications of evolutionary trends. MATERIALS AND METHODS-The species used were Crataegus douglasii Lindl., C. mollis (T. & G.) Scheele, C. monogyna Jacq., C. nigra W. et K., C. oxycantha L. var. paulii Rehd., C. stipulosa Stend., C. suborbiculata Sarg., C. tanuphylla Sarg., C. tennowana A. Nels.; Hesperomeles ferruginea (Pers.) Benth., H. glabrata Roem., H. heterophylla Hook., H. incerta (Pittier) Maguire, H. latifolia (HBK.) Roem., H. oblonga Lindl., H. obovata (Pittier) Standl., H. obtusifolia Lindl.; Mespilus germanica L.; Osteomeles anthyltidifolia Lindl., 0. schwerinae Schneid., 0. subrotunda C. Koch. Floral specimens were kindly provided by the herbaria of the University of California (Berkeley, Davis), the herbarium of the University of Vienna, and the herbarium of the Royal Botanic Gardens at Kew. The methods of preparation were described earlier (Sterling, 1964a). RESULTS-To simplify the descriptions and to miinimize repetitive details, certain conventions will be followed. The base of the carpel will be regarded as being situated just above the insertioni of the staminal bundles. This level will be the starting point from which the observer proceeds upwardly into the carpel. The observer's upward movement becomes translated ilnto movement of the entities that he observes as he goes to each progressively higher transectional level. Thus, a bundle which is in the vascular cylinder below and in the outer cortical region higher up will be described as ascending and departing centrifugally from the vascular cylinder. A bundle which is

1. The dormant shoot apex of Agathis lanceolata has a near tunica-corpus organization, which is most definite in the smaller apices. 2. The larger shoot apices have a better defined cytohistological zonation (lightly staining region of apical initials and central mother cells which gives rise to eumeristem cells on its border). These apices show more indication of periclinal divisions in the outermost layer of cells than do the smaller apices. 3. Small crystals of calcium oxalate are very abundant in the middle lamellae and primary cell walls of pith and cortex in the primordial shoot. 4. Some theoretical details of shoot apical structure are discussed.

Haplopappus gracilis (Nutt.) Gray is an aneuploid species of Compositae of wide distribution in the southwestern U.S.A. and northern Mexico. Except for 2 types of supernumeraries, cytological samples from throughout its range have regularly shown 2 pairs of chromosomes. However, recent collections from a small area in south-central Arizona had 2n = 4, 2n = 5, and 2n = 6 in the same population. The 2n = 5 plants were hybrids between the 2n = 4 and 2n = 6 types. Both natural and artificial F1 hybrids show preferential disjunction from a trivalent and produce genetically balanced gametes with n = 2 and n = 3. In backerosses of the F1 to n = 2 plants, a 1:1 ratio of 2n = 4 and 2n = 5 plants was obtained. The possible mechanisms for the evolution of n = 2 from n = 3 and vice versa are discussed. Haplopappus gracilis is anl annual composite of wide distribution in arid, semi-arid, and somewhat more mesic habitats of the southwestern United 1 Received for publication December 24, 1964. This study has been supported by Grant G 20864 from the National Science Foundation. States and northern Mexico. Cytogenetic and morphological studies (Jackson, 1962) have demonstrated that H. gracilis (n = 2) evolved from the spatially more restricted H. ravenii (n = 4) by a series of unequal reciprocal translocations and loss This content downloaded from 157.55.39.211 on Fri, 24 Jun 2016 06:38:50 UTC All use subject to http://about.jstor.org/terms

The structure of the carpel has been studied in flowers of the Neodregeae (Dipidax and Neodregea). Except in D. triquetra, which is syncarpous, the carpels are united below and free above. A dorsal bundle, two or more lateral bundles, and two placental bundles supply each multiovulate carpel. The six placental bundles of the tricarpellate pistil are united by twos in the lower part of the pistil, forming three opposite compound placental bundles in most species of Dipidax and three alternate bundles in D. triquetra and Neodregea: In the latter, an additional septal bundle continues upward as a branch from the compound placental bundle. Sutural openings are usually short and restricted to the top of the locule. All the Neodregeae have monotegmic ovules.

Intact starch grains with primulin give initially a blue fluorescence that is weakly polarized. As more dye enters the grain, the fluorescence color gradually changes to a yellow-green fluorescence that is strongly polarized. Where the structure of the grain is disorganized, the primulin-starch complex fluoresces yellow. A bright yellow rim about all intact grains is interpreted as a Becke line. Fluorescence colors of primulin-starch are essentially unaffected by hydrogen ion concentration, by the presence of salts, by the solvent in which the primulin is dissolved, and by the dye fraction (of acetoneseparated primulin fractions) used as a solute. These colors have no relation to the type of starch in the primulin-starch complex. Absorption and fluorescence spectra of primulin and its fractions vary with the concentration of the dye, the nature of the solvent, and the nature of the fraction. Three types of primulin-solvent association are envisioned: primulin anion in water; primulin molecule hydrogen-bonded to solvent or substrate molecule in non-aqueous medium; primulin dimeric association-at high concenntrations-in non-aqueous medium. Primulin-starch fluorescence colors are explicable on the basis of dye concentration and pore size in the starch grain. Pore spaces that will accept dye molecules are estimated to have a diameter between 7 and 20°.

IN AN earlier paper (Sterling, 1945), the general cytohistology and organization of the shoot apex of Sequoia sempervirens were discussed. The present article in this series is concerned with phyllotaxis and the topography of vascularization in the shoot apex. Materials and techniques are identical with those described in the paper cited above. Drawings were made by the camera lucida technique and by microprojection. The methods of Esau (1942) and Crafts (1 943a, b) were followed in the interpretation of serial longisections and transections. It is the writer's opinion that an analysis of the course of the vascular bundles in relation to leaf arrangement will provide a background for the histological details of procambial development. In addition, such an analysis is useful in considering the more general morphological relationship between "leaf" and "stem" in the shoot. The reader is referred to Arber (1930, 1941), Schuepp (1936), and Eames (1936, pp. 380-386) for general discussions on the origin and construction of the leafy shoot. REisuME OF THEORIES DEALING WITH PHYLLOTAXIS.-Although several excellent histories and critiques of theories of leaf arrangement are to be found in the literature (Church, 1920; Snow and Snow, 1931; Hirmer, 1922), it seems necessary to sum up these theories in order to introduce one which is currently finding increasing factual support. The successive leaves of a shoot are usually arranged in an ascending spiral or in alternating whorls. These leaves are spaced at relativelv constant angular distances in the horizontal plane. The angular distances, known as "divergences," have also been expressed as fractions of the periphery of the shoot. At an early date, it was evident that certain ratios were very common: 1/2, 1/3, 2/5, 3/8, 5/13,... in an apparent summation series. This particular series, initiated by the fractions 1/2 and 1/3, was given the name of the mathematician, Fibonacci. Restricted between the values of 1/2 (1800) and 1/3 (1200), the fractional values of the series gradually approach the limiting angle of 1370 30' 28.936". This angle then became the "ideal angle" for a certain school of botanists. Besides this primary series, there were also recognized various secondary series, or "Nebenkette," formed from these basic fractions: 1. 1/3 and 1/4: 2/7, 3/11, 5/18... to a limiting value of 990 30' 6", 2. 1/4 and 1/5: 2/9, 3/14, 5/23... to a limiting value of 770 57' 19", etc.

Normal and teratological carpels of Prunus laurocerasus L. are compared with each other and with the foliage leaf. The vascular structure of both types of carpels is shown to be uniquely different from that of the foliage leaf, in that the carpel has two extra bundles (either ovular or marginal) which are lacking in the vegetative leaf. These bundles, in addition to the dorsal bundle and the two wing bundles, give the carpel a basic five-trace structure. The extent of presumptive pit formation is related to the development of ovular tissue in the carpel.

TO THE INTRINSIC biological interest which attaches to the study of gall development, there is added, in the case of the grape phylloxera, an important economic consideration. Brief mention may be made of the extensive ravages of European vineyards in the latter part of the nineteenth century. The early identification of the agent as a root-infesting homopteran was attended by intensive research on its life history. Regarding this life history, one proposal of interest for the present work is that the "radicole" (root-infesting) and "gallicole" (leaf-galling) parasites are different forms of the same insect (Riley, 1874; Cornu, 1879) . In 1916, Dr. Harry Rosen described, in its broad essentials, the development of the gall of the grape leaf (Vitis vulpina L.) caused by Phylloxera vastatrix Planch. in the vicinity of Madison, Wisconsin. Using the same materials, a group of investigators currently is engaged in a more detailed study of the relationships surrounding gall formation. These materials are particularly suitable for gall study: throughout the normal growing season, new leaf primordia are produced continually; grape shoots may be kept growing the year round in a greenhouse; Phylloxera reproduction occurs through several generations during spring and summer and can go on indefinitely in a warm greenhouse; reproduction of the gall-former does not involve sexuality (some investigators have questioned the existence of a male gallicole) ; and the gall structure is relatively simple (i.e., it is a kataplasmatic gall in Kiister's [1911] sense of the term) . One investigation (Newcomb, 1951a) has dealt with respiratory relationships and terminal oxidase systems in the gall tissues as compared with normal leaf tissues. The present paper gives a detailed account of anatomical development of the phylloxera gall. MATERIALS AND METHODS.-Galled plants growing on the University of Wisconsin campus and in the entomological greenhouses were used for this study. Dr. N. C. Fassett identified the grape species as Vitis vulpina L. During 1949 and 1950, leaves of various ages were removed from near the growing ends of the shoots. Whole tips of shoots also were used for a determination of the relationship between leaf size and galling. The materials were killed in Navaschin's solution, dehydrated, and embedded following a modification of the technique of Rawlins and Takahashi (1947). Staining was accomplished with safranin and fast green. GROWTH OF THE NORMAL LEAF.-The early de

Summary Analysis of the morphological nature of the gymnospermous male gametophyte has been based on evidence from fossil gymnosperms, on a comparative survey of living vascular plants, and on ontogeny within the various families of the gymnosperms. Although fossil coniferous and taxad pollen is unknown, the fossil pollen of other gymnosperms is rather uniform in the presence of a layer of parietal cells (presumably an antheridial jacket) which surrounds a central, probably spermatogenous region. The same organization occurs in endosporal gametophytes of lower Tracheophyta of the present day. Reduction in the number of vegetative prothallial cells appears to have occurred early in gymnosperm evolution, so that the male gametophyte may be regarded essentially as a reduced antheridium. Between the fossil gymnosperms and the present forms there has occurred a reduction of the antheridial jacket and the corresponding production of a pollen tube. For various reasons, the balance of probability is in favour of a homology between the antheridial jacket of Palaeozoic gymnosperms and the tube cell of modern gymnosperms. In the lower tracheophytes and in Cordaimthus and the Recent gymnosperms, a polar organization of the endosporal male gametophyte is characteristic. On several grounds, it is shown that in this structure the presence of an antheridial stalk is precluded, and that therefore the use of the term ‘stalk cell’ is greatly in error. The cell which is often called ‘stalk cell’ is potentially–sometimes actually–spermatogenous and is sister to the virile spermatogenous cell. It is frequently sterile, however, and is therefore recognized here as the ‘sterile cell’. In the evolution of the Coniferales and the Taxales (as well as in the lower Tracheophyta) disappearance of the prothallial cells from the male gametophyte is a characteristic trend. Prothallial cells are lacking in the Taxodiaceae, Cupressaceae, Cephalotaxaceae and Taxaceae. (However, in two families, Araucariaceae and Podocarpaceae, there has developed a secondary proliferation of the prothallial cells). Recognition of the same trend in the Chlamydospermophyta and consideration of details of ontogeny indicate that prothallial cells must be absent from the gametophytes of Welevitschia and Gnetum. In these, the embryonal cell functions as an antheridial initial and produces a tube and a generative cell. The generative cell then divides into spermatogenous and sterile cells. Later, two male gametes result from division of the spermatogenous cell. Based on the morphological analyses indicated above, a terminology has been proposed which attempts to recognize morphological identities but does accept non-committal terms of common usage, as long as they do not violate the morphological concepts. A representative synonymy is given, and some examples of the use of the suggested terminology are shown. Details of the ontogeny of the male gametophyte in the conifer and taxad families have been reviewed. Although many genera are still completely unknown, it appears correct to state that on the whole the development of the male gametophyte within a family is quite uniform. The Pinaceae are characterized by the production of two senescent primary prothallial cells from the embryonal cell of the spore. The latter then serves an antheridial initial, forming a peripheral tube cell and an inner generative cell. All the preceding divisions are periclinal, and the generative cell also divides periclinally into an inner sterile cell and an outer spermatogenous cell. Eventually the latter divides to form two male gametes. In the Taxodiaceae, Cupressaceae, Cephalotaxaceae and Taxaceae no prothallial cells are formed, but the embryonal cell functions directly as an antheridial initial. Differences among these four families occur mainly in the relative sizes (and functional state) of the male gametes, the time of the occurrence of the various gametophytic divisions, and in the number of male gametes formed (which may exceed two in the Cupressaceae). In the Araucariaceae the two primary prothallial cells are not senescent but undergo an active period of cell division. Also the division of the generative cell is anticlinal rather than periclinal. Otherwise the sequence of ontogeny is similar to that of the Pinaceae. The Podocarpaceae resemble the Araucariaceae in the anticlinal division of the generative cell and usually the secondary proliferation of the primary prothallial cells. However, this proliferation is limited, and one or both cells may not divide. In one genus of the Podocarpaceae, no primary prothallial cells are produced. This article owes its inspiration to the period of the author's association with the late John T. Buchholz, Professor of Botany at the University of Illinois. It is a privilege to dedicate such a study to his memory. Professor O. H. Selling of the Swedish Museum of Natural History graciously supplied the print of PI. 1, fig. A, and Dr Walter Tulecke of the Boyce Thompson Institute kindly allowed his negative photograph to be reproduced as Pl. 1, fig. B. Dr Rudolf Florin has given both his personal permission and that of the Swedish Botanical Society to copy Text-fig. 1. Permission to copy figures from C. J. Chamberlain's Gymnosperms: structure and evolution and from the Botanical Gazette was given by the publisher, the University of Chicago Press. Many thanks are due to these individuals and organizations and to G. Fischer Verlag, Jena, J. Heslop-Harrison, editor, Annals of Botany, and P. Maheshwari, editor, Phytomorphobgy, who have allowed figures to be copied for the illustrations here.

A B S T R A C T The carpels of the Holodisceae, Neillieae, Spiraeeae, and Ulmarieae are usually separate from one another; most have open sutures, and their ovules tend to be monotegmic. The ovules are epitropic in Holodisceae, Spiraeeae, and Ulmarieae; they may be pleurotropic, apotropic, or epitropic in the Neillieae. In many species the carpels are partly fused with the floral cup. Only in Luetkea and some species of Spiraea and Stephanandra are the ovular and wing bundles separate at the base of the locule; in the other species ventral bundles persist above that level before dividing. In species with open sutures, the ovules are mostly bitegmic, and the ovular bundles tend to be separate from the wing bundles at the insertion level. An evolutionary trend towards fusion of the two ventral bundles with each other and with the dorsal bundle is shown. In Filipendula the dorsal bundle may be absent. A possible relationship between the Spiraeoideae and the Pomoideae is discussed. THE FEATURES of carpels in presumably primi