MAST, AUSTIN1*, D. SKY FELLER1, JUERG SCHOENENBERGER1, SYLVIA KELSO2, DANIELA LANG1, and ELENA CONTI1. 1Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland; 2Biology Department, Colorado College, 14 East Cache La Poudre Street, Colorado Springs, Colorado 80903, USA. - Implications of a seven-region cpDNA phylogeny and a micro-morphological survey to our understanding of floral evolution in the shooting stars (Dodecatheon) and their closest relatives among the primroses (Primula; Primulaceae)
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Researchers have previously suggested that the ca. 14 species of the
principally North American genus Dodecatheon (Primulaceae) are
closely related to Primula subgenus Auriculastrum (3
sections) based on their similar leaf vernation and cytology, as well
as cpDNA results involving single exemplars of Dodecatheon.
Dodecatheon differs from Primula in traits apparently
related to its buzz pollination, including its reflexed petals,
poricidal anthers, and lack of heterostyly. We have sampled seven
cpDNA regions (5 kb) from most taxa of Dodecatheon and the two
sections of Primula subgenus Auriculastrum found in
North America, as well as single exemplars from each subsection of the
remaining section Auricula from Europe. The combined cpDNA data
strongly supports the nested position of a monophyletic
Dodecatheon in Primula subgenus Auriculastrum.
Within Dodecatheon, sections Capitulum and
Dodecatheon are resolved as monophyletic, but section
Purpureo-tubulosa is not. We are currently screening the
single- or low-copy nuclear DNA regions leafy and waxy
for their utility in the group, and we plan to present a nuclear
phylogeny based upon one or both of these. Our micro-morphological
survey of reproductive structures in Dodecatheon and
Primula subgenus Auriculastrum documents previously
unexamined characters (e.g., the presence, shape, and distribution of
glands on sepals and petals) and re-examines features believed to
distinguish Dodecatheon from Primula (e.g., the
presence/absence of nectaries). The evolutionary history of these
micro-morphological characters and those characters traditionally used
to distinguish sections of Dodecatheon (e.g., seed shape) will
be reconstructed on the phylogeny to determine their utility in
recognizing clades within the group.
Key words: buzz pollination, Dodecatheon, Primula, Primulaceae