Schistidium deceptionense, a new moss species from the South Shetland Islands, Antarctica

Abstract

Schistidium is the richest moss genus in the Antarctic consisting of twelve species, one of which, S. deceptionense Ochyra, Bednarek-Ochyra, & Lewis Smith, is here described as new to science from the volcanic Deception Island in the South Shetland Islands archipelago in the northern maritime Antarctic. Its most peculiar diagnostic characters are strongly thickened walls of the exothecial cells; small, cupulate, and pachydermous capsules; and sinuouse laminal cells. In these features the new species shows the closest affinity to S. urnulaceum (Mull. Hal.) B. G. Bell, a South Georgian-Antarctic endemic, from which it can be distinguished by sharply keeled leaves, stout costae that are semi-terete in transverse section and strongly convex dorsally, bistratose leaf margins in 1-2 rows of cells forming bulging thickenings in the distal portion, shorter laminal cells, and larger spores. The relationships of S. deceptionense are discussed and the species is considered to belong to the Confertum group with which it shares pellucid alar region of the hyaline cells with the transverse walls much thicker than the longitudinal walls, narrow upper laminal cells, irregular and mostly strongly perforated peristome teeth, and yellow reaction of the upper leaves and leaf cells with KOH. A key to all species of Schistidium in the Antarctic is given