| Douplasia idahoensis is a rare perennial that inhabits subalpine slopes throughout central Idaho. Here I present the first reports of the species' breeding system, seed production, ovule abortion rates, and pollinator attraction systems. In addition, a survey of the species' genetic diversity is given. D. idahoensis utilizes both xenogamous and geitonogamous breeding systems. Plants excluded from insect visitors matured significantly fewer fruits than those exposed to insects. The number of seeds per capsule was relatively low for all populations sampled. Square Mountain, Elk Summit, Scott Mountain, and Swanholm Peak each had a combined two-year average of 1.61 +/- 0.62, 1.14 +/- 0.35, 1.39 +/- 0.51, and 2.69 +/- 0.92 seeds per fruit, respectively. Seed: ovule (S:O) ratios ranged from a low of 0.24 +/- 0.07 for the Elk Summit population to a high of 0.48 +/- 0.16 for Swanholm Peak. Ovule abortion rates of 15--22% of all developing seeds were observed. Light and scanning electron microscopy was used to describe the location, anatomy, and surface features of floral nectaries, osmophores, and glandular trichomes. Non-structural nectaries were found on the dorsal surface of the ovary. An average of 0.039 +/- 0.025 muL (n = 59) of nectar per flower was excreted through stomata located on the surface of the ovary. Average sugar content of the nectar was 47.41 +/- 13.97% (n = 9). Photographic techniques revealed the presence of UV patterning on the corolla which may provide visual cues to potential pollinators. Correlated with UV absorptive regions were papillate epidermal cells, which may also act as the osmophore that produces the distinctive floral odor of Douglasia. Genetic variability was evaluated in nine populations using starch get electrophoresis of soluble enzymes. At the population level, the mean number of alleles per locus (Ap) = 1.39, the average observed heterozygosity (Ho) = 0.32, and the proportion of polymorphic loci (Pp) 0.39. An analysis of allozyme banding patterns also indicated that D. idahoensis is an autotetraploid with base number x = 9. The outlook for genetic conservation appears good for this species but managers are cautioned that some populations may harbor rare alleles or unique genomes worthy of special consideration. |
