144 



MUSCINE& 



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 Sphagnaceae 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 

 part of which is the archespore, 



FIG. no. Funa.r : a hygrojnetrica. A, young 

 plant with young sporogone. B, mature plant 

 with mature sporogone ; s, seta ; f, sporange ; 

 c, calypter (natural size). C, longitudinal section 

 of sporange (greatly magnified) ; d. opercule ; 

 a, annulus ; /. peristome ; c, columel ; s, arche- 

 spore ; h, air-cavities. (After Goebel.) 



FIG. in. Mouth of sporange of Fonti- 

 nalls antepyretica L., with peristome ; 

 afl, teeth ; z^, 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 seta which is usually of considerable length, the 

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

 Sphagnum and some other genera and 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 composed 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. 



