472 CLASS BASIDIOMYCETEAE 



the Gasteromycetes in which the basidiospores are perched symmetrically 

 on the tips of the sterigmata and are not shot off, the spores reaching 

 their maturity before the spore fruit opens. 



Key to Families of Pols^porales 



Parasitic in the living tissues of leaves, growing stems, or fruits of Anthophyta 

 (Angiosperms), producing the clavate basidia externally in a continuous or 

 interrupted layer. Basidiospores becoming septate upon germination, each 

 cell giving rise to a few spindle-formed conidia. Family Exobasidiaceae 

 Saprophytic in plant tissues or on plant debris, less often parasitic. Basidia oval 

 to clavate, basidiospores germinating directly. 



Hymenium interrupted or continuous, smooth (rarely slightly roughened by 

 small wart-like emergences) , entirely resupinate or reflexed or partially stipi- 

 tate, the hymenial surface being on the under side. Spore fruit a thin weft 

 of hyphae or a more definite structure, more often papery, leathery, or even 

 corky or slightly woody. Both stichobasidial and chiastobasidial types of 

 basidia present. Family Thelephoraceae 



Spore fruits with short stipes, funnel-shaped to trumpet-shaped or almost 

 clavate, but somewhat broader and truncate at the top; fleshy; the hyme- 

 nium on the outer surface, smooth or reticulate or with low, broad, rounded 

 longitudinal ridges. Basidia stichobasidial. Basidiospores white or Hght- 

 colored. Family Cantharellaceae 



Hymenium continuous on all sides of upright filiform or clavate or much ramose 

 spore fruits which are fleshy or leathery. Both stichobasidial and chiasto- 

 basidial types present. Family Clavariaceae 



Spore fruit resupinate or reflexed or stipitate, both laterally or centrally. 

 Hymenium smooth with a number of projecting pegs or teeth or the latter 

 very numerous, being directed downward in all but a few of the resupinate 

 forms with few emergences. Spore fruits leathery, corky, woody, or fleshy. 

 The teeth are round in cross section or flattened. Basidia usually chiastic 

 but some stichic. Family Hydnaceae 



Spore fruit resupinate or reflexed, or laterally or centrally stipitate. The 

 hymenial surface is increased by the development of shallow or deep pores 

 which may be round or elongated radially with greater emphasis on the 

 radial ridges so as to form lamellae with secondary cross connections. Papery, 

 leathery, corky, woody, or fleshy. Basidia always chiastic. 



Family Polyporaceae 



Spore fruits resupinate or reflexed or laterally stipitate, fleshy, the lower fruit- 

 ing surface growing out to form numerous, elongated, separate tubes which 

 are lined internally by the hymenium. Basidia chiastic. 



Family Fistulinaceae 



Spore fruits resupinate or partially reflexed, the hymenial surface at first smooth 

 and then thrown into thick shallow ridges which often anastomose to form 

 low-walled, broad, shallow pits. Hymenium continuous over the sides and 

 edges of the ridges as well as the floor of the pits. Fruit body often more or 

 less gelatinous, with the surface in almost any direction. Many species are 

 very destructive to wood both in trees and in structural timbers. 



Family Meruliaceae 



The division of families in this order is not always as above. Patouil- 

 laid (1900) makes an entirely different arrangement. In the older works 



