Systematics/Phytogeography / Taxonomie/ Section
Bell, Hester L. .
A cryptic hybrid in Distichlis (Poaceae).
Forty years ago, a collection (Stephenson 86-304a) from Baja California was identified as a putative hybrid between MonanthochloĆ« and Distichlis. These genera are closely related and frequently occur sympatrically. Male and female plants of the putative hybrid were collected and it can be presumed to be dioecious as are all species of Distichlis. Morphologically the specimen most closely resembles a short D. spicata and shares no obvious characters with MonanthochloĆ« except a diminutive form and short leaves. Internal transcribed spacer (ITS) was cloned from the putative hybrid, D. spicata, and M. littoralis and the sequences analyzed using parsimony criteria to determine its position within the Distichlis clade. Sequences from the putative hybrid resolve as sister to the Distichlis clade. However, when ITS1 and ITS2 are analyzed separately the position of the taxon changes suggesting that recombination has taken place. Possible parental species of the hybrid (including the possibility that one parent species is extinct) and the role of hybridization and polyploidy in speciation in Distichlis will be discussed.
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1 - Rancho Santa Ana Botanic Garden, 1500 North College Avenue, Claremont, California, 91711, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 11:00 AM