Caloplaca tominii New to North America

Abstract

Caloplaca tominii Savicz occurs in Southwestern Yukon (Canada, Region of Kluane), beyond its previously known range (Central Asia, southern Norway, Greenland). The species is epigaeous, strongly basiphytic, xero- and he- liophytic. It grows in communities belonging to the Toninion coeruleonigricantis. Its occurrence in the Yukon is allowed by a strongly continental local climate in connection with periglacial phenomena. While on a botanical expedition to the Yukon Territory of northwestern Canada in summer, 1978, I had the opportunity of collecting lichens in the region of Kluane (Sheep Mountains, Slims River Valley, southwestern Yukon). The area is one of few in the Yukon for which a good phytosociological study (Hoefs et al. 1975) and species lists for crypto- gams (Hoefs & Thomson 1972; Douglas & Vitt 1976) are available. In open Artemisia-steppes on loess deposits, a sorediate yellow Caloplaca was par- ticularly abundant. Hoefs et al. (1975), in their phytosociological tables of this vegetation type, listed it as Caloplaca cirrochroa (Ach.) Th.Fr. However, my specimens from Kluane were morphologically different from C. cirrochroa, as was the ecology, since C. cirrochroa does not normally grow on soil. A specimen kindly sent to me by Dr. Hoefs was identified by Prof. Poelt (Graz) as Caloplaca tominii Sav., previously known only for southern Russia, southern Norway and Greenland. In this paper, a brief account of the morphology, sociology and distribution of Calo- placa tominii is given. Thallus brownish to light yellow (normally egg-yellow or orange-yellow), consisting of small por- tions (0.5-1.5(5) mm diam.), fused together into a larger crust. Lobes are normally absent, but small marginal lobes are sometimes present in older specimens. Soredia large (0.04-0.08 mm), light yellow, in laminar soralia or more often disposed on the upraised margin of the thallus, always very abundant. Apothecia very rare, 0.5-1.0 mm diam., with reddish-brown disk darkening with age and sorediate thick margin of the same color as the thallus. The spores have been described by Nordin (1972) from material collected in Norway: they are egg-shaped and measure 16-17 x 8-9 gm, being the largest spores in the section Gasparrinia of the genus Caloplaca. Our specimens, like those of Savicz, are all sterile. Fertile samples are known from Norway (s) and Kazakstan (LE). Specimens examined:- CANADA. YUKON: Kluane region, Sheep Mountain, earth. Hoefs, 1977 (TSB). Slims River Valley, loess deposits in Artemisio-Agropyretum yukonensis, 750 m, Nimis, 1978 (TSB, GZU). NORWAY. Oppland: Abbriiche von Gneisfelsen westlich Vagamo, Gem. Vaga um 400 m. Buschardt & Poelt, 1976 (GzU). U.S.S.R. Regio Karagandensis, Distr. Nura, steppa subdeserta, assoc. Spiraea hyperi- cifolia-Stipa lessingiana-Festuca sulcata, ad terram. Nilson & Martin, 1962 (GZU).