Pyrrolizidine alkaloid-containing toxic plants (Senecio, Crotalaria, Cynoglossum, Amsinckia
, Heliotropium, and Echium spp.).
tessellata A Not infested Aristida glauca HP Not infested Astragalus spp.
We (Li & Johnston, unpubl.) 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
Cryptic self-incompatibility in Amsinckia
calycina (Moris) Chater Bas.: Lithospermum calycinum Moris.
Ornduff R (1976) The reproductive system of Amsinckia
grandiflora, a distylous species.
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
A primary difference was that large-seeded species (seeds [greater than] 1.0 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] 0.0001).
However, in 1995 caterpillars were collected from those two most abundant host plants plus any others (primarily introduced grasses, Amsinckia
menziesii, and Montia perfoliata).
Three different species of curly top hosts were used: sugarbeet (Beta vulgaris), spinach (Spinacia oleracea), and buckthorn weed (Amsinckia
Here we report results from a phylogenetic analysis of the genus Amsinckia
, a group of western North American annual plants that has apparently undergone frequent evolutionary shifts in the mating system (Ray and Chisaki 1957a,b).
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