Pollination to Population Structure - How Understanding Reproductive Biology Can Inform Conservation of Rare Plants
Amos, Bonnie .
The Reproductive Biology of the Endangered Texas Poppy Mallow and its Cost to Conservation.
The Texas Poppy Mallow (Callirhoe scabriuscula, Malvaceae) is a rare endemic restricted to four counties in west central Texas. In 1981 it was among the first non-cactus plant species in Texas to receive endangered status. The species is restricted in distribution by soil type and has only been found in Tivoli sands. Flowering occurs during April and May. Flower production and subsequent fruit formation is highly dependent upon adequate rainfall prior to bolting and during flowering. The Texas Poppy Mallow is protandrous and is dependent upon pollen vectors for successful reproduction. Both geitonogamous and xenogamous crosses produce viable seeds. Floral attractants include nectar and pollen. A variety of insects, although most are infrequent pollinators, forage for nectar. Pollen harvesting is limited to a few species of solitary bees, including two species that have been two reported as oligolectic to Callirhoe. The oligolectic bees, because of their intra- and interfloral behavior, are the most effective pollinators. Seeds have a physical dormancy and the seed coat’s impermeability to water must be broken before germination. Below the seed coat is the nucellus, which forms a skin-like covering around the embryo and represents a second barrier to germination. Seeds readily germinate when these layers are removed. This combination of features – a specific, restricted habitat, the critical timing of rains, a strong dependency upon specific pollinators, and difficult seed germination requirements – make conservation efforts difficult and expensive. However, despite these difficulties, a recent reintroduction project has been successful at establishing a new population.
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1 - Angelo State University, Biology, Angelo State University #10890, San Angelo, Texas, 76909, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Room 3/Woodward
Date: Monday, July 28th, 2008
Time: 8:45 AM