PISTILLIDIA IN CRYPTOGAMIC PLANTS. 



223 



united to the face of the anthers, and along with them form a solid 

 mass (fig. 353). 



459. in Cryptoganiic Plants there exist organs called pistillidia, 

 which have been supposed to perform the function of pistils. They 

 consist of hollow cavities, like ovaries, to which the names of sporangia 

 (airo^*, a spore or seed, and yyo?, a vessel), and thecce (tiqxii, a sac), 

 have been given, containing bodies called spores, equivalent to ovules. 

 The sporangia or spore-cases are sometimes immersed hi the substance 

 of the plant, as in Riccia glauca (fig. 411, 1); at other times they are 

 supported on stalks or setce (seta, a bristle), as in Mosses. In Mar- 

 chantia polymorpha, they consist of distinct and separate expansions, 

 having a bottle-like form (fig. 412), the lower part, o, being enlarged, 

 containing the spores, and being surrounded by a cellular tube resem- 

 bling a calyx, c. From this ovary-like body there is a prolongation 

 which may be eonsidered as a style, t, terminated by a cellular enlarge- 



ment, s, which has been compared to a stigma. The styloid prolonga- 

 tion withers and disappears when the spores are mature. Sometimes 

 the thecse, as in Lichens, consist of a club-shaped elongated cell or 

 ascus (fig. 413, 1), containing nuclei or cells hi its interior, which form 



Fig. 411. L Perpendicular section of the frond, / of Riccia glauca, and of the sporangium 

 or spore-case, o, which is imbedded in it s, Narrow process or style by which the sporangium 

 communicates with the external surface. L, Its cavity or loculus. f, Young spores still united 

 in sets of four in the parent cells, r, Cells elongated like roots. 2 One of the cells more highly 

 magnified, with the four spores which it contains. Three of the spores are seen, the fourth 

 being concealed by them. 



Fig. 41<?. Sporangium or spore-case of Marchantia polymorpha. o, Hollow swelling contain- 

 ing spores, and which has been compared to the ovary, t, Narrow process prolonged upwards, 

 and resembling a style, s, Termination of this cellular process, compared to the stigma, c, 

 Cellular covering of the sporangium or spore-case, surrounding it like a calyx. 



Fig. 4ia 1. Theca or ascus of Solorina saccata, a species 'of Lichen, containing eight spores, 

 united in sets of two. 2. Two of these double spores highly magnified. 



