470 KUNGI IMPERFECTI. 



cells of attacked tissues. There are three modes of spore pro- 

 duction : (1) brown niacro-conidia inside the tissues; (2) colour- 

 less micro-conidia on the spots ; (3) spherical pycnidia with long 

 necks ending in a fringed opening. A sclerotial form is also 

 strongly suspected. Kemedial measures recommended are, de- 

 struction of all diseased parts, change of crop on diseased fields, 

 and selection of healthy seed and strong sprouts. 



Several other species of this genus are recorded from Xorth 

 America, but details in regard to tlieir mode of life are 

 wanting. 



Asteroma. 



Fungi forming star-like, dark-grey, mycelial patches on the 

 surface of plants. Pycnidia very small and containing tiny 

 ovoid or short cylindrical spores. Several species frequent 

 living leaves.^ 



Asteroma impressum Fuck. On Tussilago farfara. 

 A. prunellae Purt. On leaves of Prunella vulgaris. (Britain.) 

 A. ulmi Klotsch. (Britain), and A. maculare Rud. On Ubnus. 

 A. padi (D.C.) causes a leaf-fall on Primus Padiis. (Britain.) 

 A. geographicum Desm. is found on the leaves of species of Crataegvs. 

 Prumcs, and Pyrus in Europe and America. 



Pyrenochaeta. 



Pycnidia emergent or sessile, beset with bristles. Conidia 

 oblong, on branched conidiophores. 



Pyrenochaeta rubi-idaei Cav. forms black spots on leaves 

 of li't/liis Idaciis. The pycnidia are spherical with a tuft of 

 bristles projecting from their terminal pore. The conidia are 

 little, oval, and with one or two cells ; they are produced from 

 slightly In-auched conidiophores. 



Vermicularia. 



Conidia unicellular, rarely bicellular, generally spindle-shaped ; 

 they are produced inside pycnidia, and are embedded amongst 

 brown septate hairs. The species are a frequent cause of leaf- 

 spot, but most of them have not yet been sufficiently investigated. 



' Ciciuobuhis Ce-sa/ii De Baty, allied to this genus, is a parasite on Oidium 

 Tucke.ri, the dreaded vine-parasite. 



