Pyrrolizidine alkaloid-containing toxic plants (Senecio, Crotalaria, Cynoglossum, Amsinckia
, Heliotropium and Echium sp.
compared flower ontogenies between distylous and homostylous species in three separate evolutionary lineages of Amsinckia
(Boraginaceae) and found that neoteny is primarily responsible for the derivation of highly self-fertilizing species from their outcrossing ancestors.
Heterostyly, homostyly and fecundity in Amsinckia
Weller SG, Ornduff R (1989) Incompatibility in Amsinckia
grandiflora (Boraginaceae): distribution of callose plugs and pollen tubes following inter- and intramorph crosses.
Effects of thinning were greatest for Amsinckia
tesselata and for a group of relatively uncommon native annua ls.
Correlated evolution of self-fertilization and in breeding depression: an experimental study of nine populations of Amsinckia
0 mg) such as Acamptopappus sphaerocephalus, Ambrosia dumosa, Amsinckia
tessellata, Bromus madritensis rubens, Coleogyne ramosissima, Erodium cicutarium, Hymenoclea salsola, and Larrea tridentata, were underrepresented in the soil relative to trap samples, leading to significant differences in the size distribution of seeds in the seed rain and the soil seed bank [ILLUSTRATION FOR FIGURE 3 OMITTED]; G test of heterogeneity: G = 8732; df = 4; P [less than] 0.
However, in 1995 caterpillars were collected from those two most abundant host plants plus any others (primarily introduced grasses, Amsinckia
menziesii, and Montia perfoliata).
Some virus particles were found in Amsinckia
The genus Amsinckia
comprises approximately 20 species.
In contrast, Johnston and Schoen (1996) found that inbreeding depression in the highly self-fertilizing tetraploid Amsinckia
gloriosa was higher than that in selfing populations of the diploid A.
Demonstration of cryptic incompatibility in distylous Amsinckia
on the phylogeny of Amsinckia
is consistent with this view.
Here we present estimates of selfing rates and levels of inbreeding depression in nine populations of Amsinckia
, a genus with a considerable range of selfing rates among populations.
A slight, not statistically significant lowering of inbreeding depression was found in a study of nine populations, from three species, of Amsinckia
, with selfing rates estimated to range from 0.