i8o 



SECOND GROUP. MUSCINEAE. 



forms the capsule. Recurring briefly to the external form of the embryo, we remark 

 that it is usually a fusiform body, the lower extremity of which has no growth in 

 length, but swells in Sphagnum and Archidium, as it commonly does in the Hepaticae. 



The capsule originates in a globular or ovoid 

 or, as is often the case, an unsymmetrical 

 swelling below the apex of the sporogonium 

 which is now ceasing its growth ; this 

 swelling does not make its appearance in the 

 typical Mosses till after the elongation of the 

 fusiform or cylindrical sporogonium and the 

 elevation of the calyptra. Four spores are 

 produced in each mother-cell ; the prepara- 

 tion for their formation takes place at the 

 same time all through the same capsule. The 

 ripe spores are roundish or tetrahedral with a 

 delicate finely granulated exosporium, of a 

 yellowish or brownish or purple colour ; be- 

 sides protoplasm they contain chlorophyll 

 and oil; their diameter in Archidium, where 

 there are only sixteen in a capsule, is about 

 ^ of a millimetre, in the highly developed 

 Dawsom'a, according to Schimper, scarcely 

 ^i^ of a millimetre. They in many cases 

 preserve their vitality for a long time if kept 

 dry; in the moist state they germinate in a 

 few days, in Sphagnum often not till after 

 two or three months. 



The time necessary for the full develop- 

 ment of the sporogonium varies much in the 

 different species, but in most of them it is 

 very long as compared with the small size 

 of the organ in question. The Pottieae 

 produce sexual organs in summer and ripen their spores in winter ; those of Funaria, 

 which constantly have sexual organs and have sporogonia at all times of the year in 

 all states of development, require probably from one to two months to mature their 

 capsules; Phascnm cuspidatum grows in autumn from a perennial underground 

 protonema and ripens its spores some weeks before winter. The bog Hypneae, 

 on the other hand, H. gigantetim, H. cordifolium, H. cuspidatum, H. nitcns and their 

 allies, form their sexual organs in August and September and ripen their spores in 

 June of the next year, often taking ten months to perfect their sporogonia; Hypnum 

 cupressiforme has sexual organs and ripe spores at the same time in autumn, and 

 therefore takes a year to complete its course, and the same is the case with many 

 species of Bryutn and Philonotis, and with many Polytricha which form their sexual 

 organs in May and June *. 



FIG. 132. Fitnaria hy^romctricn. A rudiment of the 

 sporogonium ff in the venter * b of the archegonium, in 

 optical longitudinal section, h neck of the archegonium. 

 B, C more advanced stages in the development of the 

 sporogonium f and of the calyptra c. A magn. 500, B, C, 

 about 40 times. 



1 See Bot. Zeit. 1869, p. 344. 



