Spore Ornamentation in the Lichen Genus Solorina

Abstract

SEM study of 5 arctic alpine species of Solorina shows that each species has a dis- tinctive spore coat pattern. S. spongiosa, often thought to be an ecological variant of S. saccata, differs from that species in its spore pattern. The arctic alpine genus Solorina has five species in North America mainly well separated by num- bers of spores in the ascus, 2, 4, or 8 (Thomson 1979). The spores are thick-walled and in light mi- croscopy appear roughened. This suggested the pos- sibility that scanning electron microscopy (SEM) might bring out useful information by use of its superior resolution, depth of field, and high mag- nification. The use of SEM in lichenology was pioneered by Hawksworth (1969) with a study of cortical hyphal orientation in Alectoria and Cornicularia. Hale (1973) reported cortical characters in the Parmeli- aceae and later (1981) added studies of pseudocy- phellae and pored epicortices. Peveling (1970) con- tributed SEM and transmission electron microscope studies of surface features of a variety of lichens, and Beltman (1978) discussed the taxonomic sig- nificance of vegetative structures based on SEM preparations. Tibell (1971, 1978, 1981a,b) has con- sistently used SEM in studies of the Caliciaceae and recently (1981 b) included a study of spore orna- mentation in two species of Sphaerophorus. In the presentation of the distribution maps of Solorina in Great Britain Gilbert (1975) published SEM pho- tos of three species but did not show the details of ornamentation with sufficient clarity. The current study is a preliminary survey of the spore wall ap- pearance of the five arctic species of Solorina. Materials. The following specimens in wis were used for the photographs in this study: S. bispora, Canada, N.W.T., Axel Heiberg Island, Scotter 46106; S. crocea, Alaska, Mile 86, Haines Highway, Thomson & Ahti 21214; S. octospora, Alaska, Seward Peninsula, Cape Prince of Wales, Flock 630; S. saccata, Canada, N.W.T., Bathurst Inlet, Scotter 33566; S. spongiosa, Montana, Flathead County, along Route 2, between Essex and Summit, Ro- sentreter 2071.