Gardner, Andrew , Emshwiller, Eve .
Morphological correlates of habitat preference among the American bulb-bearing Oxalis .
The American bulb-bearing Oxalis (AMBBO) comprise a clade of about 50 species of bulb-bearing herbaceous perennials with ranges throughout the Americas. They occupy diverse habitats, including lowland riparian systems, seasonally-dry sclerophyllous forest, high elevation paramos, and bogs. Along with their wide range of habitat preferences, the AMBBO possess great morphological diversity: rhizomiform stem structures to baseball-sized bulbs; fibrous root systems to large, contractile roots; and glabrous, higher SLA leaves to hirsute, lower SLA leaves. We hypothesize that many of these morphological traits are adaptive, and may correlate more strongly with environmental preferences than phylogenetic history. To test this hypothesis, we used georeferenced herbarium specimens and a common garden to quantitatively and semi-quantitatively characterize the ranges, bioclimatic preferences, and morphologies of roughly half of the species. Phylogenetically-structured tests of correlation among morphologies and environments allow us to explore eco-morphological aspects of AMMBO diversification. Our results illustrate repeated, rapid diversification along several morphological trait axes associated with water and carbohydrate storage. Many of these diversifications are correlated with environmental factors such as total annual rainfall, precipitation and temperature seasonality. This study supports an adaptive role for morphological evolution in the diversification of the American bulb-bearing Oxalis.
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1 - University Of Wisconsin-Madison, Botany Dept, 321 Birge Hall, 430 Lincoln Drive, Madison, WI, 53706, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Franklin B/Hyatt
Date: Tuesday, July 10th, 2012
Time: 10:00 AM