FOREST PROTECTION 117 



apothecia in the succeeding spring. 

 The most important representative of 

 this family in Europe is Peziza. 

 III. Order Basidiomycetes. 



Spores carried on basidia of definite shape 

 and size, and bearing a fixed number of spores. 



1st. Family — Uredinece. 



All are injurious parasites, the 

 myceUum being in the intercellular 

 spaces of the tissues (particularly in 

 the leaves) of higher plants. These 

 fimgi change their hostplants, showing 

 a double generation, and develop sev- 

 eral kinds of asexual spores, according 

 to the season and to the host; aecidio- 

 spores and pycnoconidia in spring; 

 uredospores in siunmer; teleutospores 

 in autimin, which in the following 

 spring develop basidiospores. The my- 

 celiima from the basidiospores enters 

 the first host and develops the seci- 

 dium stage (formerly the genus Ae- 

 cidium) with secidia and pycnidia. The 

 next stage on a different host develops 

 the uredospores (formerly genus Ure- 

 do), and in autvmin the thick walled 

 teleutospores. 



2nd. Family — Hymenomycetes. 



Basidia imbedded in a common 

 hymenium which clothes, in Agari- 

 cacece, a series of radial lamellae on the 

 imder side of the pileus, and in Poly- 

 poracece and Boletacece, the inner sm*- 

 face of pores. 



In a few genera no distinctive 

 fructifications are formed (Exobasi- 

 dium vaccina, parasitic and causing 

 hypertrophy on EricacecB). 



Another arrangement of the orders 

 and families of fimgi might be made 

 with reference to pathogeny: 

 a. The groups 



UredinecB 



Ustilagineoe 

 (so-caUed "Smuts") 



Peronosjwreoe 



Exoascece 

 (witch broom) 



contain parasites only, 

 so that no proof of 

 parasitism is required. 



