THE VEGETABLE CELL. 



12S 



structure of tlie pollen-grains. Just as the latter are developed in 

 the anther without the co-operation of another organ, does this occur 

 also in the spores. In certain Cryptogarnia (the Rhizocarpese and 

 Lycopodiacese) we find the joeculiar condition, that spores of two 

 kinds are developed simultaneously, in a wholly analogous manner 

 in parent-cells, in capsular receptacles of two kinds, the spores 

 larger and smaller, possessing exactly the same structure, except 

 that one kind are larger and have a tougher outer coat. But in 

 the Rhizocarpese, only the larger exercise the function of spores, 

 the smaller, as above stated, developing the cells which contain 

 seminal filaments ; in the Lycopodiaceoe, on the contrary, both 

 kinds of spores produce plants.* 



The germination of the spores is as little dependent as their 

 origin upon a previous impregnation derived from the antheridia, 

 unless perhaps this be the case with the Charas, in which the 



Fig. 50. 



Fig, 51. 



Pro-embryo of Funaria hyqrometrica (according' to Young pro-embryo oiPteris ser 



Sehimper) a,rudunent of a bud ; &, a young stem ; c, first rulata according to Leszcyc-Su- 



development of the pro-embryo from tbe spore ; d, deve- minski. 

 lopment further advanced. 



relation of the antheridia to germination is altogether unknown- 

 In germination (except in Ghara) the spore does not grow at 

 once into a plant like the parent, but is first developed into a 

 thallus-like, cellular structure, totally devoid of vascular bundles, 

 the so-called pro-embryo, which appears under very diflEerent forms 

 in different plants of these tribes. In the Mosses (fig. 50) it pos- 

 sesses the fonn of a branched Conferva, in the Ferns (fig. 51) the 

 shape of a cordate leaflet not tinlike a frondose Liverwort, in the 



"* All error, See page 121, note; also Beporb on the Reproduction 

 of the higher Cryptogarnia, by A. Henfrey. " Tram. BrU. Assoc.'' 1851. 

 — A. H. 



