THE FUNGI WHICH CAUSE PLANT DISEASE 479 



leaves, a distinction which has been shown to be quite untenable.* 

 It is evident that much careful study by cultures and cross in- 

 oculations is needed to reveal the true status in these Fungi. 



Since the conception of species is here most loose the form species 

 given below must be regarded as purely tentative. The names are 

 to serve merely as handles for convenience in treating of the 

 various parasites and in only comparatively few instances do 

 they signify that they are really species. In many cases forms 

 appearing under two or more names may prove eventually to be 

 identical while in other cases forms may need to be sub- 

 divided. 



Key to Orders of Fungi Imperfect! 



Conidia produced in pyenidia 1. Sphsropsidales, p. 479. 



Conidia not in pyenidia 



Hyphse innate within the matrix 2. Melanconiales, p. 537. 



Hyphae somewhat superficial, often floccose 3. Moniliales, p. 564. 

 Conidia or other special reproductive cells 



unknown 4. Mycelia sterilia, p. 659. 



The Sphseropsidales 



Conidia in pyenidia which open by pores or slits, superficially 

 resembling the perithecia of the Ascomycetes. 



The Sphseropsidales are preeminently leaf-spotting fun^ though 

 many of them grow on fruit or stems causing blight, rot, cankers 

 etc. The vast majority are saprophytes or parasitic on tissues of 

 weak vitality, but not a few are active parasites. 



Key to Families of Sphseropsidales 



Pyenidia globose, conic, or lenticular 

 Pyenidia membranous, carbonous or 



coriaceous, black 1. Spharioidaceae, p. 480. 



Pyenidia fleshy or waxy, light colored. 2. Nectrioidaceae, p. 526. 

 Pyenidia more or less dimidiate, irregular 



or shield-shaped, black 3. LeptostromataceaB, p. 528. 



Pyenidia cup-shaped or patelliform, black. 4. Excipulacese, p. 533. 



