50 HANDBOOK OF MOSSES. 



lids of many of the capsules thrown off by a sort of magic 

 force ; and if the moss he is watching be a Bryum or a 

 Hypnum, the outer fringe will be thrown back like the rays 

 of a beautiful star-fish, the inner fringe all the while opening 

 and closing, and the spores shot forth, by some hidden force 

 within, a little cannonade of tiny balls, seeming as though 

 the fairies were practising their minute artillery. Or, if 

 continued dry weather has shrivelled up the mosses, so that 

 they look more dead than alive, a slight shower will at once 

 reanimate the shrivelled tufts, and he will see every moss, 

 as it drinks in the grateful fluid, waken again into life, the 

 shrivelled-up leaves once more assume their natural habit, 

 the whole mass looks like a new growth, and the sudden 

 resurrection calls to one's mind that wonderful desert plant 

 Anastatica, the Rose of Jericho. But why direct one's 

 attention to walls for watching phenomena that must be 

 common to all moss habitats ? Simply because a wall is so 

 convenient, and the whole phenomena may be watched in 

 such places without the fatigue of stooping. Stone walls, 

 mud walls, and walls of every sort and degree, are all worthy 

 of the bryologist's particular attention, and the older the 

 walls the richer the spoils as a rule. So prolific, however, 

 in mosses are these habitats, that I shall not be able to 

 mention a tithe of what may be found by an industrious 

 worker, and hence shall confine my remarks to a few of the 

 more frequent species, such as Tortula mtiralis, T. marginata, 

 Grimmia apocarpa, G. pulvmata, Brytim capillare, B. cces- 

 piticium, B. argenteum, Didymodon rubellus, and Pottia cavi- 

 folia. 



On mud-capped walls in calcareous districts, growing 

 often in greatest profusion, Pottia cavifolia may be some- 

 times found ; this is a small species, having large concave 

 leaves, often terminated by a whitish hair-like point. If the 

 leaves be examined with a lens, some peculiar membranous 

 processes will be seen attached to the veins of the upper 

 surface (fig. 26, 3 a). The capsule is egg-shaped, and the 

 mouth has no fringe, or is naked, and the lid has a short 

 inclined beak (fig. 26, 2 a). Pottia truncata (fig. 4), fre- 

 quent on all sorts of walls and banks, has a wide-mouthed 



