ALTERNATION OF GENERATIONS IN MOSSES. 



479 



calyptra, see figs. 350 = and 350 "). Ultimately this hood is thrown ott" and the 

 capsule, within which quantities of spores are produced, opens. The spores are 

 readily distributed by the wind shaking the capsule on its stalk. It should be 

 noted that in ^losses this asexual generation (the sporogonium) never becomes 

 independent of tlie sexual Moss-plant; the base of its stalk always remains embedded 

 in the tissues of the sexual generation. In the Ferns, on the other hand, the 



Fig. 351 —Alternation of Generations in Mosses. Various forms of sporogonium, which as the asexual generation 

 have been proiluced at the tips of leafy shoots. 



' Splachnuin luteum, - An unripe capsule of the same. ^ x ripe and open capsule of the same. * Splacknum vasculostim. 

 6 Longitudinal section of a ripe capsule of this Moss. ^ Sptachiium ampullaceuvi. " An unripe capsule. 8 \ ripe 

 capsule of the same. ^ and lo Sckistostega osmundacea. " A ripe capsule of the same, i, *. 6, lo natural size- 2, 8 x 2; 

 ', ». 9 X 10; 11 X 15; =• X 100. 



asexual generation ( = the Fern-plant), though at first drawing nutriment from the 

 prothallium (cf. p. 475) by its "foot", soon becomes quite independent, the prothal- 

 lium dying away. The form of the sporogonium is very varied in difierent groups 

 of Mosses. In fig. 351 are shown the sporogonia of a number of Mosses, including 

 species of Splachnum (S. luteum, S. vasciUosum, and S. ampullaceum), a rare form 

 occui'ring on the excrements of cattle, reindeer, &c., that of the already-mentioneil 

 Luminous Moss {Sckistostega osmundacea, cf. vol. i. p. 385); and in fig. 191, p. 16 



