Floral biology of Hemigenia and Microcorys (Lamiaceae)
Greg GuerinCentre for Evolutionary Biology and Biodiversity, School of Earth and Environmental Sciences, Discipline of Environmental Biology, University of Adelaide, North Terrace, SA 5005, Australia. Email: greg.guerin@adelaide.edu.au
Australian Journal of Botany 53(2) 147-162 https://doi.org/10.1071/BT04063
Submitted: 4 May 2004 Accepted: 25 November 2004 Published: 31 March 2005
Abstract
The floral morphology and pollination of Hemigenia R.Br. and Microcorys R.Br. (Lamiaceae) were examined in the field and laboratory. The protandrous flowers have tubular, two-lipped corollas. Nine floral morphotypes are described. The stamens may be completely sterile (staminodal) or have one theca reduced or absent. The anthers typically have elongated connective tissue and are mobile on the filament. When the lower end of the anther is pushed, the upper end is levered towards the mouth of the corolla tube, hence dusting the pollinator precisely where receptive stigmas will later touch. Bearding on the anthers of the adaxial stamens catches adjacent anthers so that they lever in unison. Staminodes guide insect pollinators into the throat to allow precise pollen dusting. Detailed field observations show that bees and flies are the principle pollinators of most species. Floral morphologies are related to pollinator castes, and reproductive isolation and efficiency is enhanced by precise pollen deposition. Bird pollination is likely to have arisen independently in several taxa. The floral arrangement of these taxa is superficially similar but the syndrome is achieved through different anatomy.
Acknowledgments
I thank Penny McLachlan, Bill Barker, Bob Hill, Barry Conn, Rogier deKok, Lisa Waters, Andy Austin, Ken Walker, Department of CALM Western Australia, the Plant Biodiversity Centre of South Australia and staff of Adelaide Microscopy.
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