342 



THE FUNGI WHICH CAUSE PLANT DISEASE 



Wall slightly colored 16. Cionothriz. 



Telia with a peridium 

 Telia half projecting above the 



host surface. .• 17. Dietelia. 



Telia sunken in the tissue of the 



host 18. EndophyUum, p. 353. 



Teliospores 2-celled 



Peridium present 19. Pucciniosita. 



Peridium none 20. Didymopsora. 



Melampsora Castaigne (p. 340) 



0. Pycnia half spherical. 



1. .^cia of caeoma-type, no peridium or paraphyses. 

 II. Urediniospores solitary, membrane colorless. 



III. Teliospores 1-celled, rarely 

 more, in flat irregularly limited 

 crusts. Basidiospores spherical. 



The question of biologic speciali- 

 zation is especially complicated in 

 this genus. The uredinial and telial 

 stages occur in abimdance on wil- 

 lows and poplars, the aecial stage on 

 a wide range of plants embracing 

 gymnosperms, monocotyledons and 

 dicotyledons. 



M. lini D. C. 



O. Pycnia amphigenous, numer- 

 ous, scattered, inconspicuous, sub- 

 epidermal, pale-yellow, flattened 

 globoid or lens-shaped, 100-175 ^i 

 in diameter, 65-95 ju high; spores 



Fia. 252. — ^Pucciniastrum goepper- ,,. . , o n l q_i 

 tianum, showing germinating ellipsoiu, ^— o oy o— 4 fl. 

 teUospores. After Hartig. j j^^^ ^^^Qy hypophyllous, nu- 



merous, scattered, rounded, 0.2-0.4 mm. across, bright orange- 

 yellow, conspicuous, formed between epidermis and mesophyll, 

 soon naked, ruptured epidermis evident; spores globoid, 19-27 x 

 21-28 fi.; wall colorless, thin, about 1 n, finely and evenly verru- 

 cose, with distinct papillse, pores not evident. 



