Christenhusz, Maarten , Fay, Michael , Chase, Mark .
Petenaeaceae, a new family in APG from Mesoamerica.
Petenaea cordata, a tree from northern Central America (Guatemala, Belize and adjacent Mexico) was first described in Elaeocarpaceae and later placed in Tiliaceae, based on gross morphology, but most authors have not been certain about its familial affinities. Because the morphological characters did not perfectly match any family, it was considered a taxon incertae sedis in the Angiosperm Phylogeny Group classification (APG III). A recent collection was made in Guatemala allowed us to extract fresh DNA. Analysis of both rbcL and atpB in the large Soltis et al. angiosperm matrix, the most completely sampled study published to date, indicated a moderately supported relationship to the Chinese genus Tapiscia (Tapisciaceae, the only member of the newly recognized order Huerteales in this matrix; 81% bootstrap support). We then conducted a more restricted analysis using the Bayer et al. rbcL/atpB matrix for Malvales supplemented with the other genera now placed in Huerteales from published studies (Dipentodon, Gerrardina, Huertea, Perrottetia, Tapiscia). Our results indicated a distant, weakly supported sister-group relationship to the African genus Gerrardina (Gerrardinaceae). After comparison of the characters cited in the literature and an examination of herbarium material and wood anatomy of both genera, we could find no obvious synapomorphies for Gerrardina and Petenaea, and we therefore proposed the monogeneric family Petenaeaceae. The order Huerteales now comprises four small families: Dipentodontaceae, Gerrardinaceae, Petenaeaceae and Tapisciaceae that have hardly any morphological similarities. A parallel can be drawn with Crossosomatales, another relatively new order, and also an amalgamation of small, morphologically heterogeneous families, although they are at least united by seed characteristics, which might also be the case for Huerteales.
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1 - Finnish Museum of Natural History, Botany Unit, POBox 7 (Unioninkatu 44), University of Helsinki, Helsinki, 00014, Finland
2 - Royal Botanic Gardens, Kew, Jodrell Laboratory, Kew, Richmond, N/A, TW9 3DS, United Kingdom
3 - Royal Botanic Gardens - Kew, Jodrell Laboratory, Kew Road, Richmond, N/A, TW9 3DS, United Kingdom
Presentation Type: Oral Paper:Papers for Sections
Location: Franklin A/Hyatt
Date: Monday, July 9th, 2012
Time: 4:30 PM