Kannely, Alfred , Schlising, Robert A. .
Year-round biology of the geophyte, Triteleia ixioides (Themidaceae), in mid-elevation Mediterranean California.
SPECIES of Triteleia are common but poorly studied cormous perennials in Pacific Coast states, mainly in areas of California with Mediterranean climate (warm/hot, dry summers and cool/cold wet winters). Our field study documents the basic biology and “mediterranean phenology” of T. ixioides (S. Watson) E. Greene subsp. anilina (E. Greene) L. Lenz, from three mid-elevation populations in the southernmost Cascade Range, in coniferous forests sites at 1375 and 1745 m. The plants grow in sandy-loam soils, and produce scapes to 30 cm tall, with 4-25 yellow flowers. A large bee-fly (Bombyliidae) was the most frequent flower-visitor at all sites. Experiments indicated that seed set is significantly higher in inflorescences where netting did not exclude visitors. However, natural fruit set in 2004 and 2005 ranged from only 65-74% of flowers, and only 33-56% of ovules matured into seeds. Seed weight was significantly lower in a higher elevation population, but tetrazolium tests suggested 100% viability for seeds at all sites. Dry weights (X±SE) of new (over-summering) corms in July 2005 were 0.17 ± 0.01 g. By 20 October shoots 2-4 mm long had emerged, despite total lack of roots and precipitation. After rains, by 4 November, growth produced up to 47 roots per corm, and shoots 5.4 ± 0.3 mm long; weights of corms (alone) were still not lower than in July. By February, weights of corms (0.08 ± 0.01g) collected from under snow were significantly lower than in July, and shoots (totally underground) averaged 25 ± 0.1 mm long and weighed 23% as much as the corms. Next year’s corm production begins in April (winter), on top of the old corm with a developing scape, well before the plant flowers. Seed germination also occurred during the cold, wet winter at these elevations, with radicles elongating under snow in February.
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1 - Yuba College, 2088 N. Beale Road, Marysville, California, 95901
2 - California State University Chico, Department of Biological Sciences, Chico, California, 95929-0515, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Wednesday, August 2nd, 2006
Time: 10:45 AM