Abstract Detail

Anatomy and Morphology

Gimmel, Lucie [1], Guilliams, C. Matt [2], Hasenstab-Lehman, Kristen [3].

Undescribed morphological diversity hidden in the long-straight hairs of western North American Galium L. (Rubiaceae).

Galium L. is one of the largest genera of Rubiaceae, with nearly 700 species worldwide and over 80 species in North America. Western North America, including the California Floristic Province, is a center of diversity for the genus. Fruits of Galium species are morphologically diverse, with taxa having fleshy berries or dry nutlets that can be glabrous or variously ornamented with hairs and bristles. In a previous study, Soza & Olmstead performed a phylogenetic analysis using DNA sequence data to test the monophyly of Galium groups based on fruit morphology, and examined the evolution of various fruit features using this phylogeny. In the present study, we use this published phylogeny to further examine the evolution of fruit morphology in Galium, focusing on the “long-straight hair” members of a western North American clade. We sampled specimens from two herbaria to obtain fruits of target Galium taxa. We included all available species belonging the above clade, as well as available taxa across the genus defined by the “long-straight hair” fruit type. We used Z-stacked microphotography to obtain high resolution fruit images and a compound microscope to capture microphotographs of single hairs. We developed a set of qualitative and quantitative characters that describe types of straight hairs in Galium. Members of the western North America clade seem to show differences in trichome length, density, width, and shape. We used ancestral state reconstruction to explore congruence between hair morphology and the molecular phylogeny of Soza & Olmstead. We conclude with a revised hypothesis about the morphological evolution of these features.

1 - Santa Barbara Botanic Garden, 1200 Mission Canyon Road, Santa Barbara, CA, 93105, United States
2 - Santa Barbara Botanic Garden, Department of Conservation and Research, 1200 Mission Canyon Road, Santa Barbara, CA, 93105, USA
3 - Santa Barbara Botanic Garden, Department of Conservation and Research, 1200 Mission Canyon Road, Santa Barbara, CA, 93105, United States

Keywords:
none specified

Presentation Type: Poster
Session: P, Anatomy and Morphology Posters
Location: Arizona Ballroom/Starr Pass
Date: Monday, July 29th, 2019
Time: 5:30 PM 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: PAM012
Abstract ID:971
Candidate for Awards:None