MOUTH OF THE CAPSULE DESTITUTE OF TEETH.
C'apsule Valvular.
Genus 1. Andraca. Capsule quadrivalve ; the valves held in proximity at the apex by means of the persistent lid ; calyptra irregularly torn.
Of this genus, first defined by Ehrhart, and adopted by liedwig and by all subsequent muscologists, four species are known, all of which are indigenous to Bri tain. They are inhahitants of alpine rocks ; of a very dark colour, and rigid texture. Linnxus, who was acquainted with two of the species, having overlooked the columella and persistent lid, described them as Jungermanniae. They would have been published under the name now universally received, in the Methodus Muscorum of the younger Linnxus, had he not, with misplaced indignation, cancelled Ehrhart's original sheet, eontaining the alteration, and restored his father's ar rangement. The nearest affinity of this genus, among Foliose 'Mosses, ia to Sphagnum, on aacount ol its sessile capsule. The species most prized is A. nivalis, (Muse. BI it. t. 8.) one or the two with nerveless leaves, a moss peculiar to Britain, which is chatacterised by the stems being slightly branched, leaves loosely imbricated, sub falcate, subsecund ; those or the perichaetium to those of the stem.
a. Capsule sessile, receptacle pedunculate.
II. Sphagnum. Receptacle pedunculate, peduncle resembling a fruitstalk. Capsule sessile, entire, its lid deciduous, its mouth naked ; calyptra irregularly torn.
Contains four species, all of which were compre hended, by Linnmus, under his Spin palustre, and are common in marshy situations and bogs. By colour alone they may be easily discriminated from all other British mosses, except Dicranum glaneum.
b. Capsule on a fruitstalk, receptacle sessile.
11 I. Phascum. Fruitstalk terminal. Operculum ad nate. Caly ptra dimidiate, (short, fugacious.) Contains 17 British species, according to Sir J. E. Smith, (Comp. Fl. Br. 2d and 3d edit.) w Inch are reduced in the AInse. Brit. to 11 species.
The Phasca are among the minutest mosses known, and Ph. serratum, the smallest species, is, besides, re markable for its creeping, articulated, br.mched, leaf less conferva-like shoots, which aripear to be merely the primal y expansions of the seed in germination, persistent in this instance, as the primary lichenoid expansion of Acrostichum alcicorne is among ferns. In most of the
Phasca the fruitstalk is very short, and the fruit immersed among the perichaetial leaves.
IV. Voitia. Fruitstalk terminal. Operculum adnate. Capsule deciduous with the fruitstalk. (Calyptra large, persistent.) This genus was first defined by Professor Hornschuch, on account of a moss, (V. Nivalis, Muse. Exot. t. 97. the only species at present known) which Ile found by the snow line on the Carinthian mountains. The genus is distinguished from Phase= by the large persistent calyptra, and the deciduous fruitstallt, which, in the only species known, is about an inch in length ; and the whole habit is very unlike that of any known Phascum.
V. Gymnostomilm. Fruitstalk terminal. Aloud) of the capsule naked. Calyptra dimidiate.
Contains fourteen British species, according to the AIuse Brit. and nine foreign mosses, considered as spe cies of this genus, are figured in the 'Muse. Exot. Among these foreign species are the mosses which had been comprehended In the new genus Leptostornum, by the distinguished Mr. Brown ; a tribe of plants marked by a vet y peculiar habit ; gibbous capsule, approaching, in some instances, to the fortn of that of Diphyscium; and at) annular membrane arising within the walls of the cap sule, traversing its mouth. As a horizontal membrane, with a similar origin, has been found to cover the month of the capsule of four British species, (most easily per ceived in G. griffithianum) the Leptostoma have been pro visionally included by Dr. Hooker within his definition of Gymnostomum. In that genus plants of such singularly different habits are now included,that it seems not unlikely that the discovery of a few new species additional tnay in duce muscologists, not tnerely to replace Leptostomum, (perhaps with some alteration in the character,) but to form generic definitions for other parcels of Gymnostomum as at preseot constituted. Giyphocarpa of Brown, in particuiar, we wish much to see separated.