192 



CLASS CEYPTOGAMIA. 



in texture, form, and color ; they are leathery, woody, leaf-like, 

 white, yellow, green, and black ; they are seen on stones, old 

 fences, and buildings ; some with strong, green filaments are 

 suspended from branches of trees, and improperly called mosses. 

 The fruit of the Lichen consists of cups or shields called apothe- 

 cia, in which the seeds are contained. Fig. 163, a, represents a 

 lichen of a leaf- 

 like appearance ; 

 here the apothe- 

 cia, imbedded in 

 the thallus, are 

 very apparent. 

 5 is a lichen re- 

 sembling a d rink- 

 ing-glass. c is the 

 reindeer moss, 

 furnishing a,l- 

 most the solefood 

 of that animal, so important to the Laplander. Li the middle 

 of Europe this lichen grows only to the hight of two or three 

 inches ; but in Lapland it sometimes attains to the hight of one 

 or two feet. Litmus^ which is so common as a chemical test for 

 acids and alkalies, is obtained from a species of white lichen, 

 called archil ; this is also used for giving a crimson color to 

 wool and silk. The powder called cudbear^ used for dyeing 

 purple, is obtained from a lichen. 



290. Fungi^ the sixth Order^ contains the IfusTirooms^ or 

 fungus plants ; these exhibit no appearance of green herbage ; 

 they are generally corky, fleshy, or mold-like. The fruit of 

 some is external, of others internal. They are often of very 

 quick growth and short duration. The genus Agaricus^ which 

 contains the common eatable mushroom, has a convex, scaly, 

 white head, called Sipileus j this is supported on a stalk called 

 a stirpe. On the under surface of the pileus, or cup, are seen 

 many flesh-colored membranes called gills ; these in the young 

 state of tlie mushroom, are concealed by a wrapper called 

 a volva^ which is considered as a kind of calyx. As the mush- 

 room becomes mature, the volva bursts and remains upon the 

 stipe, while the pileus released from its confinement extends 

 upward and exhibits an imeven appearance u]3on its edge,* 

 caused by its separation from the volva. Fig. 164 rej^resents 

 'at a the gills running from the stipe to the circumference under 

 the pileus ; J, a young mushroom with the pileus of a globular 

 form and not separated from the volva ; <?, the volva, or wrap- 

 per bursting and separating from the pileus so as to exhibit 



U8e(8 of Lichens.— 290. Fungi or Mushrooms. 



