Samydaceae are a family of flowering plants formerly placed in the polyphyletic Flacourtiaceae. Samydaceae have sometimes been segregated from Flacourtiaceae (e.g., by Bentham and Hooker) as the group with well-developed hypanthia, and this tradition has been maintained in many African floras. Recent analyses based on both morphological and molecular data indicate that Samydaceae are a monophyletic and monothetic group related to Salicaceae, which now also include many former Flacourtiaceae. Some authors (e.g., Chase et al., 2002) even place Samydaceae in a broader Salicaceae. However, Samydaceae share many symplesiomorphies with other Malpighialean families, such as Passifloraceae, and show few obvious morphological connections to Salicaceae.
Like many other closely-related taxa in the Malpighiales, Samydaceae have introrse anther dehiscence, parietal placentation, and arillate seeds. They also have synapomorphies which are useful for field identification: pellucid-punctations and/or -lines (usually in the leaves) and deciduous leaf teeth (theoid type). Almost all members of the family have minute flowers. The largest genus in the family is Casearia, which has more than 180 species, and the number of species coupled with the size of the flowers has left the family largely unstudied.
The genus Casearia is pantropical, Osmelia and Pseudosmelia are from Indo-Malesia, Ophiobotrys and Trichostephanus are from tropical Africa, and all of the other genera are neotropical.
Shrubs or trees. Leaves alternate, pinnately veined, rarely acrodromous (Lunania), infrequently entire but more commonly with deciduous conical teeth (theoid teeth), rarely with spinose margins (Casearia sect. Casearia unranked group Ilicifoliae), rarely with stellate pubescence (Ryania), lamina often with pellucid-punctations or -lines, stipulate or exstipulate. Mostly hermaphroditic, infrequently dioecious (Euceraea, Neoptychocarpus, Osmelia, Pseudosmelia?), rarely monoecious (Trichostephanus) or polygamous (Ophiobotrys). Inflorescences usually axillary fascicles/glomerules or reduced to single axillary flowers, less commonly corymbs, racemes of spikes, or panicles of spikes. Flowers often minute, wider than 2 cm only in Ryania and Samyda. Hypanthium generally present, sometimes reduced or lacking. Sepals 4-7, possible less in Lunania but hard to tell due to early splitting, imbricate. Petals absent. Disk usually present, adnate to the calyx, and alternating with or inside the whorl of stamens, in some genera (e.g., Casearia) appearing like staminodes or a fleshy corona. Stamens 4 to numerous, typically inserted in 1-3 whorls, sometimes connate to various degrees, anther dehiscence introrse or rarely latrorse (Lunania). Gynoecium of one pistil, ovary superior, unilocular, placentation parietal, ovules few to numerous, styles usually 1 or distally 3(-5)-branched, 3 in Osmelia and Pseudosmelia, stigma usually capitate, rarely sessile. Fruits fleshy or dry 3-valved capsules, occasionally indehiscent. Seeds arillate (except Tetrathylacium) or with long, cottony hairs (Casearia sect. Gossypiospermum).
Molecular Biology and Genetics
Statistics of barcoding coverage
Specimens with Sequences:5550
Specimens with Barcodes:4027
Species With Barcodes:503
Salicaceae or the willow family (although they contain more than just the willow genus, Salix) is a family of flowering plants. Recent genetic studies summarized by the Angiosperm Phylogeny Group has greatly expanded the circumscription of the family to contain 55 genera.
In the Cronquist system, the Salicaceae were treated in their own order Salicales, and contained only three genera (Salix, Populus and Chosenia), but APG includes it in Malpighiales. The additional genera were previously treated in Flacourtiaceae, but had a mixed history before that and have been treated in Bembiciaceae, Caseariaceae, Homaliaceae, Poliothyrsidaceae, Prockiaceae, Samydaceae, and Scyphostegiaceae. The Samydaceae (including Caseariaceae) appear rather distinct and might be a valid family however.
Genera[edit source | edit]
References[edit source | edit]
- "Family Salicaceae". Taxonomy. UniProt. Retrieved 2010-02-04.
- "Salicaceae Mirb., nom. cons.". Germplasm Resources Information Network. United States Department of Agriculture. 2003-01-17. Retrieved 2010-02-04.
- Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 (and more or less continuously updated since).
- Alford, M. H. (2006). "Gerrardinaceae: a new family of African flowering plants unresolved among Brassicales, Huerteales, Malvales, and Sapindales". Taxon 55 (4): 959–964. doi:10.2307/25065689. JSTOR 25065689.
- Boucher, L. D.; Manchester, S. R.; Judd, W. S. (2003). "An extinct genus of Salicaceae based on twigs with attached flowers, fruits, and foliage from the Eocene Green River Formation of Utah and Colorado, USA". American Journal of Botany 90 (9): 1389–99. doi:10.3732/ajb.90.9.1389. PMID 21659238
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