218 



PLANT LIFE. 



the first spore so formed another spore is produced as the first 

 grows older ; and this process continues as long as the 

 plant is able to furnish material for the making of spores. 

 In such cases, often the oldest spores are liberated while 

 new ones are being produced at the base of the chain. 



A modification of the production of spores singly occurs 

 when the branch destined to produce them gives rise to 

 two to eight very slender branches, each of which enlarges 

 at the tip into a single spore, so that the main branch appears 

 to carry two to eight spores upon slender stalks. Such a 

 spore-producing branch is called a basidium (fig. 213). It is 

 the characteristic form in the higher fungi, which produce 

 conspicuous fructifications. 



Fig. 214. — A, a puffball (Octaviana) halved, showing the internal chambers (shaded 

 dark) lined by hymenium (the narrow white border). The intervening spaces, g, 

 and the unshaded outer part are formed of interwoven hyphs. Magnified 5 diam. 

 B, a bird's-nest fungus (Crttczbuluiii) halved. The similar internal chambers have 

 been loosened by the disappearance of the intervening hyphaj immediately about the 

 hymenium (represented by radiating lines) and a wavy stalk by which each remains 

 loosely attached. Magnified 4 diam. — After Luerssen. 



314. Fructifications. — In the higher fungi whose myce- 

 lium is developed within a dead substratum many branches 

 are aggregated to constitute a reproductive structure or fructi- 

 fication, which is the only conspicuous part of the fungus. 

 (For an account of the vegetative parts, see ^f^f 50, 54.) 



