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Reproductive alternatives to insect pollination in four species of Thalictrum (Ranunculaceae)
Author(s) -
STEVEN JANET C.,
WALLER DONALD M.
Publication year - 2004
Publication title -
plant species biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 36
eISSN - 1442-1984
pISSN - 0913-557X
DOI - 10.1111/j.1442-1984.2004.00103.x
Subject(s) - biology , pollination , anemophily , ranunculaceae , pollinator , botany , pollen , ovule , insect , hand pollination
Abstract Although insect pollination is ancestral in the angiosperms, selection has favored wind pollination and self‐fertilization in many lineages. The evolution of clonal growth may have also decreased dependence on insect pollinators. We investigate transitions away from insect pollination in the genus Thalictrum (Ranunculaceae) among four species that vary in pollination syndrome. Thalictrum sparsiflorum is insect pollinated and self‐fertilization may also provide reproductive assurance. Thalictrum alpinum is clonal, has a floral morphology associated with wind pollination and is self‐compatible. Thalictrum fendleri is a wind‐pollinated and dioecious species that sets few fruits naturally and invests little in sexual reproduction, possibly due to a trade‐off with clonal growth. Thalictrum dioicum is also wind‐pollinated and dioecious, but does not grow clonally at our sites and has a higher investment in sexual reproduction than T. fendleri . The pollen : ovule ratio is largest in wind‐pollinated species, but varies considerably among them, possibly reflecting differences in pollination efficiency and/or incidental insect pollination. None of the species appear pollen limited in the study populations, suggesting that factors other than pollen receipt limit female fertility at these sites.