Alvear, Marcela , Almeda, Frank .
The genus Monochaetum (Melastomataceae) in Colombia (South America).
Monochaetum, is a neotropical genus of shrubs with close to 60 species restricted to montane habitats in Mexico and Central America, Northern Andes in South America (Colombia, Venezuela, Ecuador and Peru) and reaching the Guayana Highlands. Based on morphology, cytology, and preliminary molecular data, Monochaetum appears to be monophyletic and sister to other pĂˇramo genera (Castratella and Chaetolepis) within the Melastomeae clade. The genus is characterized by its 4-merous flowers, prevailingly dimorphic stamens with dorsally appendiculate anthers, capsular fruits that are free from the hypanthium, and cochleate seeds. The most recent monograph treats only the Mexican and Central American species (20 species). The South American species remain poorly understood; they were last treated by Gleason (1929) in an abbreviated synopsis (30 species). Subsequent regional treatments for Ecuador (three species), Venezuela (12 species), Peru (four species) and Guyana (one species) have all been based on limited materials. Colombia stands out as a major center of diversity for the Melastomataceae (62 genera, 910 species) and also for Monochaetum with 28 species, 19 of which are endemic. This study presents the first comprehensive regional monograph of Colombian Monochaetum based on morphology. Detailed descriptions of all taxa, a taxonomic key, species distributions, and ecological information, along with a summary of karyology are presented. Over 1100 collections were studied for the revision, 900 of which were from European and US herbaria, 200 from Colombian herbaria including our own collections. Future work will include combined molecular and morphological phylogenetic analysis as well as a treatment for the Flora Neotropica.
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1 - California Academy of Sciences, Department of Botany, 55 Concourse Drive, Golden Gate Park, San Francisco, California, 94118, USA
Presentation Type: Poster:Posters for BSA Sections
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM