232 PHYLUM VII. CARPOMYCETEAE 



(&) Make very thin cross-sections of several of the gills and 

 carefully mount in water or alcohol. Note the layer of spore- 

 bearing cells (hymenium), with basidiospores borne upon little 

 stalks. 



(I) Examine the pores of fresh polypores in transection, 

 looking for the basidia and basidiospores in the pores. 



(m) In like manner make transections of Prickly Fungi, 

 Coral Fungi, and Leathery Fungi, but in these look for basid- 

 iospores on the outer surface of the sections. 



CLASS 16. TELIOSPOREAE. THE BRAND-FUNGI 



392. Here are collected a considerable number (4200 

 species) of extremely parasitic fungi, certainly related to 

 the fungi of the two preceding classes. On account of 

 their excessive parasitism they are structurally much re- 

 duced and degraded and this has served to hide their true 

 relationship. 



393. The plant body consists of branching septate 

 filaments which run through the green tissues of higher 

 plants, eventually producing usually erumpent spore 

 clusters (sori), but no definite spore fruits (perithecia, or 

 apothecia). Conidia of one or two kinds are usually 

 present, and precede the formation of teliospores. 



394. The Rusts (Order UREDINALES) are minute, 



parasitic, greatly degraded fungi 

 which grow in the tissues of higher 

 plants. 



395. A common Wheat rust 

 (Puccinia graminis) may be taken 



FIG. 112. Development ... t . . ,, 



of aeciospores and pycnio- as an illustration of the order. It 



is common wherever wheat is 

 grown, and often greatly injures and sometimes entirely 

 destroys the crop. Its round of life shows four well- 

 marked stages, as follows: (I) In the spring clusters of 

 minute yellowish cups occur on the leaves of the 



