The Spread of the Moss Hyophila involuta in Ontario

Abstract

The moss Hyophila involuta (Hook.) Jaeg. was discovered on the calcareous walls of most ofthe locks in the Rideau Canal system in southeastern Ontario. The species, known in Canada only from Ontario, apparently has been spread northwards in the water and on the boats travelling through the locks from more southern localities in the United States to its northernmost Ontario locality of 45025 'N latitude. The moss Hyophila involuta (Hook.) Jaeg. (Pot- tiaceae) has always been a rare species in Canada, and at present, is known there only from Ontario. It was first collected in this country by John Ma- coun, who discovered it on limestone rocks in the Bruce Peninsula, along the Sydenham River, Owen Sound, Grey Co., 17 September 1890 (CANM 198186). Kindberg (Macoun & Kindberg 1892) de- scribed the plants two years later as Leptodontium canadense Kindb. in Mac. & Kindb., which Chen (1941) synonymized with H. involuta. Ireland and Cain (1975), in a checklist of Ontario mosses, re- ported its occurrence in three counties: Essex, Lin- coln, and Grey. Later collections added three more counties: Hastings, Peterborough, and Welland. Within each of these counties Hyophila has been collected from only 1-3 localities, all in the Caro- linian (Deciduous) and Great Lakes-St. Lawrence Forest Regions in the southeastern part of the prov- ince. In Ontario, as elsewhere, the plants grow in or near water, on wet limestone or calcareous sand- stone rock or boulders in and along creeks and rivers and also near waterfalls. In Essex County, the south- ernmost county in Ontario, the species is known only from two islands in Lake Erie: East Sister and Pelee.