CRYPTOGAMOUS OR FLOWERLESS PLANTS. 



499 



ceous than foliaceous. Their structure is, as it were, anticipated 

 in Riccia, above mentioned (Fig. 1170). They are by no means 

 aquatic, however, but grow on the ground, on the bark of trees, or 

 on the surface of exposed rocks, to which they cling by their lower 

 surface, often with the greatest tenacity, while by the upper they 

 draw their nourishment directly from the air (Fig. 1174). The 

 fructification is in cups, or shields (apotJiecia, Fig. 1176), resting 

 on the surface of the thallus, or more or less immersed in its sub- 

 stance (Fig. 1178), or else in pulverulent spots scattered over the 

 surface. A magnified section through an apothecium (Fig. 1176) 

 brings to view a stratum of elongated sacs (asci), with filaments 



1176 1177 1179 



intermixed, as seen detached and highly magnified at Fig. 1177. 



FIG. 1174. A stone upon which several Lichens are growing, such as (passing from left to 

 right) Parmelia conspersa, Sticta miniata, Lecidea geographica (so called from its patches re- 

 sembling the outline of islands, &c., on map?), &c., &c. 1175. Piece of the thallus of Parme- 

 lia conspersa, with a section through an apothecium. 1176. Section of a smaller apothecium, 

 more magnified. 1177. Two asci and their contained spores, with the accompanying filaments, 

 highly magnified. 1178. Section of a piece of the thallus of Sticta miniata, showing the im- 

 mersed apothecia. 1179. Cladonia cocc'mea, bearing its fructification in rounded red masses 

 on the edges of a raised cup. 



