2 28 PLANT LIFE. 



hymenomycetes in the spores being formed inside the 

 body of the fungus, which is generally spherical or pear- 

 shaped, and is, in some cases, entirely subterranean. 

 The best known of these fungi are the Puff-balls. 

 Scleroderma, one of these gastromycetes, is from i to 3 

 inches in diameter and when fully ripe, consists of a 

 mass of minute blackish or purple spores contained in 

 a sort of membranous sack. When trodden upon, the 

 sack bursts and the spores are scattered by the explo- 

 sion like a cloud of dust. They are then either carried 

 off by the wind, or stick to the fur of the animal which 

 trod upon the plant. Lycoperdon is very similar though 

 smaller ; but it differs in the pear-shaped or globular 

 sack containing, besides the spores, a peculiar entangle- 

 ment of fine fungus threads, the " capillitiuvil' which 

 prevents the spores from being carried off at once. 

 They come out in small quantities whenever the ripe 

 fungus is touched. Both these forms are found in 

 woods, either on the ground or near tree stumps ; and 

 occasionally, also, they are met with in meadows or 

 pasture. The little Birds nest Fungus {Cyathus or 

 Crucibuluni) occurs on the bark of trees or on the soil ; 

 it is very like a minute brown tumbler, ^ to |^ inch 

 across, and contains numerous little round bodies, each 

 attached by an elastic cord to the bottom of the 

 tumbler. These bodies contain the spore-bearing 

 cavities and the elastic string is used in their distribu- 

 tion. Another genus, Nidularia, only differs in the little 

 egg-like bodies being free and not attached to the cup. 

 Another very large group of fungi, the Ascomycetes, 

 is to be found on decaying sticks, old wood, often 

 below the bark, or upon animal dung. They are 

 distinguished botanically by the spores being found 

 inside long oval tubes called asci. The group is a very 



