Gaga, a new fern genus segregated from cheilanthes (pteridaceae)
Abstract
Ongoing molecular phylogenetic studies of cheilanthoid ferns confirm that the genus
Cheilanthes (Pteridaceae) is polyphyletic. A monophyletic group of species within
the hemionitid clade informally called the "C. marginata group" is here shown to be
distinct from its closest relatives (the genus Aspidotis) and phylogenetically distant
from the type species of Cheilanthes. This group is here segregated from Cheilanthes
as the newly described genus, Gaga . In this study, we use molecular data from four
DNA regions (plastid: matK, rbcL, trnG-R; and nuclear: gapCp) together with spore
data to circumscribe the morphological and geographical boundaries of the new genus
and investigate reticulate evolution within the group. Gaga is distinguished from
Aspidotis by its rounded to attenuate (vs. mucronate) segment apices, minutely bullate
margins of mature leaves (vs. smooth at 40 ×), and less prominently lustrous and striate
adaxial blade surfaces. The new genus is distinguished from Cheilanthes s. s. by its
strongly differentiated, inframarginal pseudoindusia, the production of 64 small or
32 large spores (vs. 32 small or 16 large) per sporangium, and usually glabrous leaf
blades. A total of nineteen species are recognized within Gaga; seventeen new combinations
are made, and two new species, Gaga germanotta and Gaga monstraparva , are described.
© Copyright 2012 by the American Society of Plant Taxonomists.
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https://hdl.handle.net/10161/5988Published Version (Please cite this version)
10.1600/036364412X656626Publication Info
Li, F; Pryer, KM; & Windham, MD (2012). Gaga, a new fern genus segregated from cheilanthes (pteridaceae). Systematic Botany, 37(4). pp. 845-860. 10.1600/036364412X656626. Retrieved from https://hdl.handle.net/10161/5988.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Kathleen M. Pryer
Professor of Biology

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