Tholurna dissimilis Well Established in Western North America

Abstract

With 47 localities, Tholurna dissimilis is now shown to be widely distributed in Western North America. Previously considered restricted to tops of krummholz or timberline tree-tops, it has been found also among tree-tops of a coastal lowland forest at an elevation of only 150 m above sea level. fairly extensive botanical excursion activities in western Canada and the USA in Washington and Oregon during the last ten years have considerably broadened our knowledge of the distribution of Tholurna dissimilis (Norm.) Norm. in North America. eight known localities reported ten years ago (Otto 1972) have now increased to 47. Several of the new records are from Garibaldi Provincial Park in British Columbia, and the Mt. Baker area in the state of Washington, where Tholurna had been reported earlier (Otto 1972). Noteworthy new localities. --BRITISH COLUMBIA: Little Mt. Hooper N of Cowichan Lake, 4901 'N, 124028'W, Pojar 760584 (UBCL); Mt. Whymper, Pojar 760060 (UBCL); Michel Peak, 530N, 1260W, Pojar 79012 (UBCL); unnamed peak between Lagopus Lake and Astlais Mtns., 54047'N, 126048'W, Pojar 1015 (UBCL); Two Sisters Mtn., Pojar (UBCL 8687); Schulbuckhand Creek, Pojar (UBCL 12281); Kettlehole Pass, 57035'N, 128047'W, Pojar (UBCL 8654); Haines triangle, Otto 5908 (UBCL); Glacier Lake, Schofield & Donovan 76606 (UBCL); Fern Lake, 57045'N, 124047'W, Hamilton (UBCL 10369); Nusatsum River, 52030'N, 126030'W, Pojar 790142 (UBCL); NORTHWEST TERRITORIES: Tlogotsho Plateau, 61*08'N, 124033'W, Ahti 32767 (UBCL); Howards Pass, 62027'N, 129012'W, Rosie 44 (CANL); YUKON: Francis Lake, 61024'N, 129030'W, Rosie (CANL 62461). Two collections from Vancouver Island, British Columbia (Pojar 760584 & 760060) are the first reports from an insular locality in North America. Until recently, all North American records have been from higher elevations, usually at timberline, but a collection was made at an altitude of 400 m (Pojar 790142), and another (Pojar UBCL 12281) unexpectedly in a lowland locality (elevation 150 m) in the Kitimat Valley of west-central British Columbia. Dr. Pojar (pers. comm. 1978), while collecting cones by helicopter for a B.C. Forest Service reforestation project, noticed that a removed tree top and terminal branches of a spruce tree were covered with Tholurna dissimilis. tree was about 40 m tall and the tallest tree in the local canopy. Pojar (in litt.) described the climate of the site as follows: The locality is roughly midway between the cities of Terrace and Kitimat, and its macroclimate may be assumed to be intermediate. Terrace receives about 1100 mm annual precipitation, whereas Kitimat experiences more oceanic influence with 2300 mm total annual precipitation, and has more frost free days than Terrace. regional climate is suboceanic, a warm temperate rainy climate with no distinct dry season and generally cool moist summers. However, the north-south trend of this large valley provides a pathway for the flow of cold arctic air during the winter, when the area is commonly affected by maritime polar and maritime arctic air 007-2745/83/263-265$0.45/0 This content downloaded from 207.46.13.124 on Wed, 22 Jun 2016 05:52:38 UTC All use subject to http://about.jstor.org/terms 264 THE BRYOLOGIST [Volume 86