Hilpertia velenovskyi (Musci, Pottiaceae) New to the Arctic from Ellesmere Island, Northeastern Canada

Hilpertia velenovskyi (Schiffn.) Zander is reported new to the Arctic. Hilpertia scotteri (Zander and Steere) Zander is treated as a synonym of H. velenovskyi, and a full description is given. This is only the third locality known from North America of this now monotypic genus. Hilpertia velenovskyi is considered a xerophyte centered in Eurasia from central east Europe to China with northern disjunct populations in continental Asia, and disjunctions in Pre-Holocene refugial regions of Canada. While reading "the red book of Pottiaceae" (Zander 1993) the text and illustrations of Hilpertia gave the first author a hint as to a possible identity of a plant he collected in 1990 at Tanquary Fiord, Ellesmere Island, Arctic Canada, while joining Sylvia Edlund in field work. The identity of this plant was confirmed by the second author as the genus Hilpertia. This genus is unique among the Pottioideae in the elaboration of a photosynthetic organ consisting of thin-walled and hollow-papillose laminal marginal cells rolled in a spiral tube (Zander 1989). Only two previous records document the presence of Hilpertia in North America. The first specimen was collected in 1977 by G. W. Scotter in the Northwest Territories, District of Mackenzie, Nahanni National Park, and it formed the basis for Tortula scotteri Zander & Steere (Zander & Steere 1978). The collection site was the upper part of a lacustrine, calcareous deposit of silt mixed with minor portions of sand and clay. Phytogeographically, the collecting site is located well within the montane forest zone. The second specimen was collected in 1984 by T. McIntosh in British Columbia, Big Bar area, N of Lillooett in a shrub-steppe habitat. This specimen was also referred to Tortula scotteri. This collection came from semi-arid steppe of the interior Cordilleran region. The third specimen, reported here, was collected by G. S. Mogensen in 1990 on Ellesmere Island, Tanquary Fiord, on marine shoreland beach of silt with some sand on a flat terrace about 5 m a.s.l. These plants (Fig. 1) occurred as scattered individuals or in to aggregations, with the characteristics "cabbage-head" appearance as noted also by McIntosh (1989) in his specimen. Phytogeographically, the Tanquary Fiord site is located in the high arctic region at 81?23'N. Taxonomy.-Zander (1993) recognized two species of Hilpertia: H. velenovskyi (Schiffn.) Zander and H. scotteri (Zander & Steere) Zander, the former of Eurasia and the latter endemic to Canada. Tan and Zhao (1997) reported new finds from China and new observations in the morphological variation of H. velenovskyi in western and alpine China, both in leaf morphology and in operculum shape. They drew the conclusion that the two species are conspecific i.e., that H. scotteri is a synonym of H. velenovskyi. We concur with this conclusion. Geographic distribution.-Tan and Zhao (1997) summarized the phytogeographic distribution of Hilpertia velenovskyi (including H. scotteri) as having a "broad northern boreal range". This characteristic does not apply to Canadian populations which are all confined to xeric habitats in steppe, montane forest, or high arctic regions. We note that localities in China also are xeric. Furthermore, we note that both the collection from Nahanni River and from the high arctic dessert are located in regions with incomplete glacial cover during later stages of the Pleistocene. In light of this information we prefer to consider H. velenovskyi a xerophyte centered in Eurasia, occurring from eastern Europe to China with northern disjunct populations in continental Eurasia and Canada. We are aware of specimens only from the Northern Hemisphere, but have noted that Van der Wijk et al. (1969) cited the presence of Tortula velenov0007-2745/99/753-755$0.45/0 This content downloaded from 157.55.39.100 on Thu, 25 Aug 2016 05:07:22 UTC All use subject to http://about.jstor.org/terms 754 THE BRYOLOGIST [VOL. 102 :1 bI\\ ,'i ;?; ~ In I i a i ?: v, I ~ -~ ~ ::: 9) !3: O