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Abstract Detail

Systematics Section/ASPT

Penneys, Darin S. [1], Almeda, Frank [2], Michelangeli, Fabian [3], Fritsch, Peter [4].

A survey of remarkable evolutionary trends in the Melastomataceae.

The Melastomataceae rank among the ten largest angiosperm families, comprising ca. 20 tribes, 170 genera, and 5000 species. Recent and ongoing phylogenetic investigations on the Melastomataceae have yielded novel strongly supported groupings based on multiple genes, necessitating many taxonomic changes. These new taxonomic alignments prompt a reassessment of many remarkable morphological, ecological, and biogeographical trends in both systematic and evolutionary contexts. Some characters that have undergone modification include stem vascularization, crystal inclusions, chromosome number, leaf venation patterns, growth form, pollination syndromes and rewards, breeding strategies, androecial morphology, fruit types, and seed features. Pollinator shifts from bees to vertebrates such as hummingbirds, passerines, bats, and rodents have arisen independently in at least five tribes (Miconieae, Merianieae, Blakeeae, Sonerileae, Tibouchineae). Melastome pollinator rewards include oils, pollen, nectar, and floral food bodies; morphological modifications of the androecium are closely linked to pollinator shifts. Ant-plant associations are found in the Henrietteeae, Miconieae, Blakeeae, Cyphostyleae, Sonerileae, and mite-plant associations are even more widespread. Clades within some tribes represent model cases of adaptive and/or explosive radiation in tropical ecosystems (e.g., Blakea, Dissotis, Gravesia, Medinilla, Memecylon, Meriania, Miconia, Microlicia, Tibouchina), whereas comparable diversifications are notably lacking in other tribes (e.g., Kibessieae, Bertolonieae, Rhexieae). Gravesia, a near-endemic, monophyletic genus of Malagasy melastomes with ca. 110 species, evolved a bewildering range of growth forms as they exploited available niches across the isolated island. Medinilla, a paraphyletic genus with at least 400 species distributed throughout Paleotropical wet forests, may have the most extensive natural range of any melastome genus, and it has equally broad vegetative and reproductive morphological variation.

Broader Impacts:

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1 - California Academy of Sciences, Golden Gate Park, 55 Music Concourse Drive, San Francisco, CA, 94118, USA
2 - California Academy of Sciences, Department of Botany, 55 Music Concourse Drive, Golden Gate Park, San Francisco, CA, 94118, USA
3 - The New York Botanical Garden, Institute of Systematic Botany, 2900 Southern Blvd., Bronx, NY, 10458, USA
4 - California Academy of Sciences, 55 Music Concourse Drive, SAN FRANCISCO, CA, 94118-4503, USA

character evolution
seed morphology

Presentation Type: Oral Paper:Papers for Sections
Session: 39
Location: Elmwood/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 8:30 AM
Number: 39001
Abstract ID:316
Candidate for Awards:None

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