FLESHY AND WOODY FUNGI 219 



long axes of the spindles in both divisions are commonly transverse to 

 the long axis of the basidium. The spores in all of the forms studied 

 by him are uninucleate at first. Just when the mycelial cells become 

 regularly binucleate has not been certainly ascertained except in a few- 

 forms. Presumably in Coprinus radiatus the uninucleate spores give 

 rise to uninucleate hyphal cells, but Levine finds in his Boletus studies 

 that the primary spore nucleus divides at once to form two nuclei. 

 Presumably, the nuclear division in other forms may be delayed, until 

 the primary mycelium has arisen. An alternation of generations com- 

 parable to that of the rusts is also present in the Hymenomycetes and 

 Gasteromycetes. The sporophyte begins at some indefinite point in 

 the mycelium and extends through the development of the carpophore. 



A. Hymenomycetes. — The undivided basidia of these fungi bear 

 four basidiospores perched on corresponding points, or sterigmata. 

 These basidia spring directly from the mycelium in the primitive forms, 

 but in the more highly evolved types, the basidia are borne on definite 

 layers (hymenial layers) together with the paraphyses and cystidia 

 characteristic of some of the forms. The hymenia are carried by special 

 fruit bodies which differ structurally in the different f amiUes. These 

 fruit bodies arise from a profusely branched mycelium, which radiates 

 through the organic substratum, which may consist of leaf mold, rotten 

 wood, dying tree trunks, and manurial waste. The hyphal cells are 

 frequently united by clamp connections which probably give greater 

 strength to them. Such are the saprophytes. Some of the hymeno- 

 mycetous fungi are parasites and five in the bark and wood of trees, 

 and some few are parasitic on the woody parts, leaves, flowers and 

 developing fruits of certain shrubs. Sometimes, as in Armillaria mellea, 

 the hyphae become united in strands with apical growth. These strands 

 are known as rhizomorphs and serve in part as the resting organs. True 

 sclerotia are also formed. The fruit bodies take various forms. The 

 most highly developed types with stalk, cap and gills are known as 

 toadstools. Some of the simple forms are club-shaped. Others have 

 spines and pores instead of gills over which the hymenia are spread. 



Family i. Dacryomycetace^. — The fruit body is gelatinous, or 

 cartilaginous, and of different shapes. The whole surface of the fructi- 

 fication is covered with a paHsade-like layer of long club-shaped basidia 

 which bear two-forked basidia, each fork with a basidiospore. Conidio- 

 spore formation occurs in a number of forms. The important genera 



