Hooper, Elisabeth , Yatskievych, George .
What is “Aleuritopteris farinosa”? Insights from spore morphology and sporangial capacity.
Aleuritopteris FĂ©e is a predominantly Old World genus of about 50 species with a center of diversity in the Sino-Himalayan region. Molecular phylogenetic studies place the genus in the ‘hemionitid’ clade within the cheilanthoid ferns (Pteridaceae; Cheilanthoideae). However, there is no set of morphological features that unambiguously defines the genus and generic and subgeneric circumscription has been problematic and inconsistent. Aleuritopteris is typified by A. farinosa (Forssk.) FĂ©e, itself a systematically challenging taxon. Historically, it has been treated as a single, variable species with a broad geographical range or as a species complex containing between 15 and 37 taxa. Given its importance in defining Aleuritopteris, this type “species” has become the focus of a comprehensive systematic study. Here we present the result of a survey of spore morphology and sporangial capacity using light and scanning electron microscopy. Mature spore size, perispore ornamentation, and number of spores per sporangium were determined for approximately 300 herbarium specimens representing at least 22 putative taxa. These new data will be used to test hypotheses about species delimitation based on standard macromorphological features. In addition spore data should prove useful in detecting cases of polyploidy, hybridization, and/or apomixis, all of which have been documented previously in A. farinosa s.l.
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1 - Truman State University, Biology Department, 100 E Normal Street, Kirksville, Missouri, 63501-4221, USA
2 - Missouri Botanical Garden, Po Box 299, St Louis, Missouri, 63166-0299, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Alpine B/Snowbird Center
Date: Monday, July 27th, 2009
Time: 11:30 AM