EUTHALLEPHYTA EUMYCETES TOADSTOOLS, ETC. 233 



AUTOBASIDIOMYCETES 



The basidia of the hymenium more or less club-shaped, undivided; sterig- 

 mata usually 4, occasionally 2, 6, or 8, coming from the apex of the basidium. 

 The Dacryomycetineae with long club-shaped basidia and two long sterigmata. 

 Basidiospores large ; spores divided before germination ; includes the group 

 Dacryomycetineae, and an unimportant group, the Exobasidiineae, or small 

 gall parasites containing the Exobasidium which occurs upon the cranberry and 

 blueberry. The third group, Hymenomycetineae, contains a number of poison- 

 ous plants and will be treated more in detail. 



HYMENOMYCETINEAE 



Mycelium of septate hyphae, loose or delicate in texture or made up into 

 strands or hard masses; hymenium at the time of spore formation free; the 

 basidia form a definite layer or hymenium which may cover the whole surface 

 of the fruiting body, or may be restricted to a definite portion; the fruit is 

 made up of more or less closely compacted threads, hyphae, grown together, 

 or it may be delicate and somewhat ephemeral; the hymenium may be free 

 or gymnocarpous or covered from the beginning; the covering is called the 

 veil, which consists of a layer of threads extending from the margin of the 

 cap to the stem, or the veil may envelop the entire plant ; the volva is an 

 envelope which in the young stage completely covers the plant; at maturity it 

 is left in the form of a cup at the base of the stem or distributed from the 

 cap to the base of the stem; the annulus is a ring around the stem formed by 



Fig. 69. Cross section of Bracket Fungus. 

 Polyporus igniarius. h. Fungus threads, hyphae be- 

 tween the pores. s. Hymenium surrounding the 

 pores; a number of basidia with spores. After 

 Luerssen. 



Fig. 69A. Mushroom (Agari- 

 cus campestris). To the left a ma- 

 tured plant and to the right a young 

 plant. (Strasburger, Noll, Schenck 

 and Schimper). 



