Submitted to: Prairie Naturalist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/24/1997
Publication Date: N/A
Citation: Interpretive Summary: Purple coneflower is an abundant forb of the central and northwestern Great Plains. To discover if this plant could serve as a surrogate species in studies of the genetics of certain species of rare rangeland plant, we examined its breeding system and identified the insects that pollinate it. We found purple coneflower to be an acceptable subject for r genetic studes: It is partially self-compatible but primarily outcrossing, and is pollinated mostly by native solitary bees. Studies using it in place of rare species are proceeding.
Technical Abstract: We describe aspects of the reproductive biology of purple coneflower (Echinacea angustifolia D.C.), a common forb in the central and northwester Great Plains. The inflorescences (capitula) flowered centripetally and florets were protandrous: stigmas were receptive approximately 24 h after another dehiscence. Estimated pollen viability ranged from 86% to 99% Purple coneflower exhibited a mixed breeding system: it was primarily xenogamous (66% of achenes from xenogamy treatments were viable), but was partially self-compatible, occasionally producing viable achenes from geitonogamous (9%) or autogamous (7%) hand pollinations. Seed fitness characteristics, such as presence of an endosperm, achene weight, and germination capability were significantly higher in naturally pollinated florets and xenogamous crosses than in selfed treatments. Pollen was transported by insects, and not by the wind. Insect visitors included 13 wild bee species in four families, and four families of butterflies.