Breutelia tundrae (Bartramiaceae), a new moss species from the Cape Horn Archipelago (Prov. Antártica Chilena, Chile)

Abstract

Breutelia tundrae is newly described from southernmost Chile. It seems to be restricted to the Magellanic tundra, and thus its name. It is distinguished by the expanded, appressed leaf base, often with lax cells at the shoulders, widest well above the insertion, with only scant alar differentiation. The upper laminal cells are long-rectangular, very thick-walled, and porose. It seems closest to the northern Andean B. karsteniana, which is similar in aspect. However, B. tundrae differs from B. karsteniana in having leaves slightly more spreading when dry (or moist) and somewhat shorter. In addition, the laminal cells are shorter, broader, even thicker-walled and more porose. The projecting prorulae are slightly taller than those in B. karsteniana. The species are best differentiated by differences in their leaf bases. In B. karsteniana they are spreading from the insertion and widest immediately above the insertion in the area of the extensively differentiated alar cells; in B. tundrae the leaf base is appressed to the stem, almost always orange, and widest well above the insertion and there are only 1–3 differentiated alar cells. A key to the species of Breutelia in the Cape Horn Archipelago is provided.