Search

Iridaceae are one of the largest families of Lilianae and probably also among the best studied of monocotyledons. To further evaluate generic, tribal, and subfamilial relationships we have produced four plastid DNA data sets for 57 genera of Iridaceae plus outgroups: rps4, rbcL (both protein-coding genes), the trnL intron, and the trnL-F intergenic spacer. All four matrices produce similar although not identical trees, and we thus analyzed them in a combined analysis, which produced a highly resolved and well-supported topology, in spite of the fact that the partition homogeneity test indicated strong incongruence. In each of the individual trees, some genera or groups of genera are misplaced relative to morphological cladistic studies, but the combined analysis produced a pattern much more similar to these previous ideas of relationships. In the combined tree, all subfamilies were resolved as monophyletic, except Nivenioideae that formed a grade in which Ixioideae were embedded. Achlorophyllous Geosiris (sometimes referred to Geosiridaceae or Burmanniaceae) fell within the nivenioid grade. Most of the tribes were monophyletic, and Isophysis (Tasmanian) was sister to the rest of the family; Diplarrhena (Australian) fell in a well-supported position as sister to Irideae/Sisyrinchieae/Tigridieae/Mariceae (i.e., Iridoideae); Bobartia of Sisyrinchieae is supported as a member of Irideae. The paraphyly of Nivenioideae is suspicious due to extremely high levels of sequence divergence, and when they were constrained to be monophyletic the resulting trees were only slightly less parsimonious (

Phylogenetic relationships of Limoniastrum and other genera of subfamily Staticoideae (Plumbaginaceae) were studied using parsimony analysis of the plastid gene rbc L, the intron of trn L and the intergene spacer of trnL - trn F. Our analysis showed that Limoniastrum was polyphyletic.Limoniastrum ifniense , in both rbc L and combined data analyses, is sister to Armeria andPsylliostachys , whereas in the trn L-F (intron and spacer combined) analysis it is sister to a clade composed ofAcantholimon , Dictyolimon and the remaining species of Limoniastrum. In all analyses, the five remaining species of Limoniastrum (excluding Limoniastrum ifniense) formed a clade with two groups of species L. monopetalum+L. guyonianum and those sometimes considered as the segregate genus Bubania ( L. feei, L. weygandiorum and L. rechingeri). Levels of sequence divergence among these three groups of Limoniastrum were greater than for other well supported genera in the family and, in combination with morphological differences and paucity of synapomorphies, led us to conclude that separate generic status for each of the three clades is warranted.

The stigma ofCaesalpinia pulcherrimais crateriform. The crater continues as a slit-like canal through the style and into the ovary. Both crater and canal are lined by several layers of fusiform and thin-walled cells which are continuous in two narrow regions in the ovary. Post-anthesis and before pollination, the middle lamella of cells lining the stigmatic crater and stylar transmitting tissue undergoes dissolution. This occurs in a progression down the style with cells separating partially or wholly from neighbours. Dissolution is initiated at intercellular junctions where wall fibrils loosen and variously-sized and -shaped holes appear. Cytoplasmic changes include increased dictyosome activity, increased rough and smooth endoplasmic reticulum at the periphery of cells and accumulation of electron opaque deposits at the plasma membrane. The crater fills with stigmatic fluid and the diameter of the stylar canal increases. Pollen germinates in the secretion-filled crater, and pollen tubes grow down the style between the cells of the transmitting tissue but do not enter the canal. They emerge at the entrance to the ovary cavity and grow over one or two narrow strips of ovarian transmitting tissue cells which are present throughout the length of the ovary close to the ovules. This ensures that tubes grow in close proximity to the micropyles.

Phylogenetic relationships of Limoniastrum and other genera of subfamily Staticoideae (Plumbaginaceae) were studied using parsimony analysis of the plastid gene rbc L, the intron of trn L and the intergene spacer of trnL - trn F. Our analysis showed that Limoniastrum was polyphyletic. Limoniastrum ifniense , in both rbc L and combined data analyses, is sister to Armeria and Psylliostachys , whereas in the trn L-F (intron and spacer combined) analysis it is sister to a clade composed of Acantholimon , Dictyolimon and the remaining species of Limoniastrum. In all analyses, the five remaining species of Limoniastrum (excluding Limoniastrum ifniense ) formed a clade with two groups of species L. monopetalum+L. guyonianum and those sometimes considered as the segregate genus Bubania ( L. feei, L. weygandiorum and L. rechingeri ). Levels of sequence divergence among these three groups of Limoniastrum were greater than for other well supported genera in the family and, in combination with morphological differences and paucity of synapomorphies, led us to conclude that separate generic status for each of the three clades is warranted.