144 



MUSCINEyE 



The impregnated oosphere, or oosperm, develops into an embryo, 

 from which is derived the sporogone within the ventral portion of the 

 archegone. After investing itself with a cell-wall, it divides by a number 

 of longitudinal, radial, and transverse septa. At an early period in 

 typical mosses the young elongated sporogone ruptures transversely the 

 wall of the venter, the lower part of which forms a sheathing protection 

 to its base, and is termed the vagine, while the upper part becomes 

 elevated in the form of a cap or calypter. In the Sphagnacese the sporo- 

 gone attains almost perfect development before the- rupture of the 



archegone; in other mosses the 

 '^ ■ various portions of which the 



sporange is composed are diffe- 

 rentiated only at a later date. 

 The sporange is at first filled 

 with fluid contents, the greater 

 ■^ frtflit l a^^'^jja^iUfiy \ part of which is the archespore, 



Fig. iio. — Fnnariti hygromeirica, A^ young 

 plant with young sporogone. B^ mature plant 

 with mature sporogone ; j, seta ; f, sporange : 

 Ct calypter (natural size). C, longitudinal section 

 of sporange (greatly magnified) ; d, opercule ; 

 a, annulus ; p^ peristome ; c, columel ; 5, arche- 

 spore ; /i, air-cavities. (After Goebel.) 



Fig. iti. — Mouth of sporange cS Fonti- 

 nalis antepyyetica L., with peristome : ' ' 

 ap^ teeth ; ip^ cilia ( x 50), (After 

 Schimper.) 



developing into the mother-Cells of the spores, from each of which are 

 produced four spores by free-cell formation after preliminary indica-. 

 tion of bipartition. The withered neck of the archegone, which has 

 assumed a deep reddish brown colour, may often be recognised for 

 some time surmounting the apex of the calypter. The mature sporogone 

 consists of a pedicel or ^/a^which is usually of considerable length, the 

 lower portion or foot being enclosed within the vagine, but is short in 

 Sphagnum and some other genera — arid the sporange or spore-capsule 

 surmounted by the calypter, while the base of the seta is surrounded by 

 the sheath-like vagine. The wall of the sporange is coniposed of several 

 layers of cells, the outermost of which has a distinctly epidermal cha- 

 racter, and is sometimes perforated by stomates with imperfect guard-cells. 



