Additions to the boreal flora of the Northwest Territories with a preliminary vascular flora of Scotty Creek

Abstract

We present the first survey of the vascular flora of Scotty Creek, a peatland-dominated watershed with discontinuous permafrost about 60 km south of Fort Simpson, Northwest Territories (NWT). Of the 140 vascular plant taxa found at Scotty Creek, two are additions to the boreal flora of NWT: Arethusa bulbosa (Dragon’s-mouth, Orchidaceae) and Carex pauciflora (Few-flowered Sedge, Cyperaceae). The occurrence of Arethusa bulbosa extends the known range of this species 724 km to the northwest, making this purportedly eastern American plant almost pan-Canadian. Two other major range extensions (> 200 km) are reported for Carex brunnescens subsp. sphaerostachya (Round-spike Brownish Sedge) and Platanthera dilatata var. dilatata (Tall White Bog Orchid). Furthermore, 15 other rare NWT species are reported, including three species known from a single other locality in the NWT. The flora of Scotty Creek is dominated by circumpolar (55%) and widespread North American (34%) elements. Despite the absence of exposed alkaline rocks and the dominance of deep organic soil almost throughout Scotty Creek, a number of limeindicator plants were found in lakes and minerotrophic wetlands.