In form the capsule varies very much. It is roundish in Bartramia ; pear-shaped in Funaria hygrometrica ; subulate in Tortula ; gibbous, or roundish on one side and flat on the other, in _Diphyscium and Buxbaumia ; quadrangular in some Polytricha, Ste.
in direction, the capsule is either upright, and equal on every side, as in Gymnostomum (excluding Mr. Brown's Leptostornum,) Orthotrichum, Sclotheimia, Stc. or as it is mole or less inclined (cernuous) when the di mension of the upper side is usually greater than that of the lower ; as in most Hypna, many Dicrana, Etc. When inclined, it is sometimes furnished with a little marnilliform appendage towards the base, termed Struma, as in Dicranum virens, strumiferum, Scc.
In colour the capsule varies very considerably, thougli this character has not hitherto been found of much conse quence. Yet it is very striking in some foreign mosses; is yellow, for instance, in Gymnostomum zanthocar pum ; Dicranum flexifolium and Drepanophyllum fulvum, it is of a brownish-yellow ; in Calymperes Gar neri it is of a reddish-brovvn, Esc.
From the base of the capsule to its apex, arises an upright little pillar, termed Columnula, or Columella. This is universally present in the fruit of mosses. Its apex is considered by Hedwig as heing always attached to the high-est part of the interior of the operculum. In Buxbaumia aphylla it is narrow at the base, becomes ventricose towards the rniddle, and narrower again to wards the summit. It is curiously bent as it passes from the inner wall of the capsule towards the apophysis. In this moss, at least in its younger state, the lower parts of the colurnella is hollow. In Gymnostomum pyriforme, it appears as if attached to the base of the capsule by a number of roots ; and in the upper part assumes the forms of a drinking glass. In the genus Sphagnum, it is an obtuse cone.
Sometimes, as in Systilium splachnoides, and Hyp num dendroides, it remains attached to the operculum after the opening of the capsule. In the latter men tioned specics, by contracting upon itself, it shuts the capsule by bringing down the operculum close upon its mouth, in moist weather, and raises it again when the weather becomes dry. Its summit is club-shaped, in
Tay loria splachnoides, in Lyellia, at maturity, it seems to be terminated by the horizontal membrane, of which a part adheres to it ; in Dawsonia, it terminates in nume rous cilia. The use of this part is supposed by Hedwig to be, to promote the circulation of the juices of the cap sule in its early state, and afterwards, probably, it adds to its firmness.
The capsule is supported on a peculiar elongated receptacle termed Seta, or Fruitstalk, which is produced after the flower. It is vvanting only, as already men tioned, in Sphagnum and Andraea, in which the capsule is sessile. It is very short in Diphyscium foliosum, in most species of Phascum, in Grimmia apocarpa maritima, in Cinclidotus fontinaloides, in the genus Fon tmalis, Etr.c. in which the capsule does not rise above the periclixtial leaves. Usually the capsule s very con siderably elevated above them. In Bryum riquetrum it is very long, reaching to three, or even five inches above the leaves, The fruitstalk varies very considerably in colour. Its surface is generally smooth ; but it is covered with pa pillxform excrescences, in Buxbaumia aphylla, Hypnum rutabulurn, velutinum, lutescens, &c. At the summit, in several instaoces, it expands considerably, forming a part termed Apophysis. This part is small compared with the capsule, in those Polytricha that are furnished with it. In Tayloria it is long and narrow. Of all genera hitherto known, it is most remarkable in Splachnum, some species of which, it is several times larger than the capsule itself, and is usually of a different colour both from the capsule and the fruitstalk. Splachnurn Splixricum the apophysis is from twice to three times larger than the capsule ; in Splachnum rubruni and lu teum, it is umbrella•shaped ; and the capsule appears merely like the top, or little ornament, above the um brella. In the former of these two fine foreign species, the apophysis is of a deep red, in the latter, of a brilliant yellow.