Hepatic and hornwort flora of Singapore

Abstract

The primary aim of this study was to investigate and document the hepatic and hornwort floras of Singapore. The secondary aim was to compare and understand the changes in the species composition through time in a highly urbanized island environment like Singapore. As presented, a total of 74 species in 37 genera of Hepaticae and Anthocerotae are known from Singapore. Aneura, Cololejeunea, Cyathodium, Folioceros, Harpalejeunea, and Notothylas are new generic records. Thirty-eight species are reported as new for Singapore. Identification keys to the genera and species of Singapore hepatic and hornwort floras are provided. Short descriptions are provided for each species. Of the 74 species, 21 are regarded as possibly extinct from the island on the basis of no recent collections. An additional 16 records could not be confirmed due to lack of voucher specimens and recent collections. Taxa suffered most from the urbanization of environment seem to be those of the genera Bazzania and Frullania. A moderate 40% extinction rate over a period of two centuries was calculated for the liverwort and hornwort floras of Singapore. Their local disappearance is probably caused by forest clearing and the subsequent change of air humidity and, in the case of corticolous species, most probably due to the increased air pollution.