THE FUNGI WHICH CAUSE PLANT DISEASE 



599 



Branches circinate at apex; conidia 



mesogenous, muricate 3. Acrospeira. 



Branches spirally twisted; conidia 



exogenous 4. Streptothrix, p. 599. 



Hyphae simple or with straight 



branches 5. Virgaria. 



All hyphae more or less creeping 

 Branches curved or lash-like. . . 6. Campsotrichum. 



Branches not curved ' 



Conidia spiny, rarely smooth 7. Zygodesmus, p. 599. 



Conidia smooth 



Conidia sessile 8. Trichosporium. 



Conidia on stalks 

 Conidia on tooth-like sterig- 



mata 9. Rhinocladium. 



Conidia on jar-like stalks .... 10. Basisporium. 

 Hyphae forming a crust, parasitic 11. Glenospora. 



Streptothrix Corda 



Conidiophores erect, monopodially branched, 

 the branches spirally coiled; conidia apical or 

 lateral, single, sessile or with short sterigmata, 

 dark colored. 



A small genus. S. dassonvillei Broc-Ros. is 

 noted as the cause of mold of grain and fod- 

 der.3" 



Zygodesmus Corda 



Hyphie and conidiophores creeping, the lat- 

 ter branched, light or dark colored, here and 

 there irregularly inflated, septate at the swel- 

 lings; conidia globose or ovate, muricate, rarely 

 smooth, on short sterigmata or on basidia-Hke 

 branches of the sterigmata. 



Some fifty species, chiefly non-parasitic. 



Z. albidus E. & H.^ 



Halsted describes a disease characterized by a flourj' coating 

 on violet leaves and ascribes it to this species. 



Fig. 401. — Periconia. 

 After Saccardo. 



