Abstract Detail



Reproductive Processes

Taylor, David [1], Anderson, Gregory [2].

Cryptic Dioecy in Stigmaphyllon subgenus Ryssopterys (Malpighiaceae).

Stigmaphyllon subgenus Ryssopterys (Malpighiaceae) is a group of 22 species of woody vines endemic to coastal and other low-elevation sites in parts of island chains in Southeast Asia and Oceania.  These species have been characterized as being androdioecious, but studies have not been carried out to test if these species do indeed manifest this rare sexual system, or if the apparently hermaphroditic flowers are functionally female.  If confirmed, the latter would recast these species as functionally dioecious.  We have carried out Scanning Electron Microscopy analysis of pollen grains of 11 of these species and found results that correspond to the presence of cryptic dioecy, with pollen grains in morphologically hermaphroditic flowers bearing inapeturate, and thus sexually nonfunctional, pollen grains. This is the first known observation of dioecy in Stigmaphyllon.  Stigmaphyllonsubgenus Ryssopterys is nestedwithin Stigmaphyllonsubgenus Stigmaphyllon.  The latter is endemic to South America and has functionally hermaphroditic flowers. Thus, our discoveries suggest that the dioecious condition in this genus evolved after dispersal to island chains in Southeast Asia and Oceania.  The pollen-bearing sexually-nonfunctional stamens in subgenus Ryssopterysfemale flowers might serve as attractants for pollinators, as landing platforms for pollinators (as is the case for functionally dioecious species ofSolanum) or fodder for pollinators, whose identification is a part of ongoing studies.


1 - University Of Portland, Biology Department, Swindells Hall 108, MSC 163, 5000 N Willamette Blvd., Portland, OR, 97203, United States
2 - University Of Connecticut, Department Of Ecology & Evolutionary Biology, 75 N. Eagleville Road, Unit 43, Storrs, CT, 06269, United States

Keywords:
Stigmaphyllon
Ryssopterys
Malpighiaceae
cryptic dioecy.

Presentation Type: Poster This poster will be presented at 6:15 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PRP008
Abstract ID:591
Candidate for Awards:None


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