Moss Habitats.
By James E. Bagnall.
(Continued from page 272.)
A moss-grown tree is always an attractive object to me, and many a pleasant hour has been spent looking over these mossy invaders in search of some rare or local species. The trees most prolific in moss tenants in Warwickshire, (better known to me than any other county,) are the ash, elm, lime, Ontario poplar, sycamore, and apple. The oak is often moss-grown, but not to the extent of the above-mentioned, nor are its inhabitants so truly tree-loving species. On the beech and the conifers I rarely find mosses. In other climates these also have their special tenants. The mosses which I should designate tree-loving mosses are such as the Orthotrichums, Cryphæa, Leacodon sciuroides, Zygodon, Weissia cirrhata, Leskea polycarpa, &c.
The Orthotrichums ave very distinct looking mosses, occurring in larger or smaller tufts. The fruit-stalks are very short and usually hidden by the surrounding leaves. The capsules with one exception are striated or streaked, and always erect, the calyptra bell-shaped, longitudinally plaited, and more or less covered with erect hairs, the leaves in most cases erect when dry, and more or less covered with minute papillæ, and the leaf margin in most cases turned over towards the upper surface or involute, leaf cells roundish. If the above characters are borne in mind they will be great helps.
Orthotrichum affine will be found frequently en the ash, elm, and poplar in large, loose, dark green tufts, a rather coarse-looking moss, with a pale yellowish-green calyptra. The capsule is oblong, pale brown, with a longish straight beak when ripe, but becomes whitish and somewhat spindle-shaped when dry.
O. Lyellii is abundant here on the elm and ash, forms large yellowish-green loose tufts, has the leaves much recurved when moist, twisted when dry, the leaf margins plane, and both surfaces covered with prominent papillæ or minute elevations, and much clothed with brownish jointed conferva-like processes. The fruit very rare.
O. diaphanum will be found in many habitats, trees, old palings, walls, &c. It grows in small bright-green tufts, and has the leaves terminated by translucent toothed whitish tips.
O. leiocarpum is rare in the Midlands, and is readily known from the other species by the capsule, which is quite smooth, i.e., without striæ, when dry, This I find on the Ontario poplar.
The Ulotas have most of the characteristics of the Orthotrichuims, but have usually more hairy calyptras, and narrower loaves, much crisped when dry.
Ulota crispa, which occurs on both elm and ash, forms little yellowish-green tufts, and has the leaves much twisted when dry. From May to July is the best season for all the above in perfect fruit.
