The orchids in the Ottawa district: Floristics, Phytogeography, population studies and historical review

Abstract

The Ottawa District is the area within 50 km of the Peace Tower of the Parliament Buildings in Ottawa, Ontario, Canada. Within these parts of eastern Ontario and western Quebec, 44 species of orchids have been recorded since 1856. Of these, six species are provincially rare in Ontario and 13 in Quebec. This report is presented as a baseline study from which to design further research and prepare effective planning measures to protect wild orchid populations. It includes information on identification, past abundance, population changes, development cycles and relative stability of colonies. The history of collecting and recording (including the work of the Native Orchid Location Survey), principal orchid habitats, local distribution patters, rare species, colour forms and other topics are discussed in an introductory section. Detailed information on these topics is presented for each species, when relevant, together with a brief description of the plant, the overwintering shoot, capsules and seeds, blooming dates and colony sizes, all based on herbarium specimens, literature and 30 years of many species are described, and detailed population studies are included for Corallorhiza striata, Goodyera pubescens. G. tesselata, Platanthera hookeri, P. orbiculata and Spiranthes cernua. The distributions of some species are shown to correlate with the Canadian Shield or the St. Lawrence Lowlands, or with calcareous rock, sandstone or sand deposits.