490 FUNGI IMPERFECTI. 



throughout the whole summer. Fischer has proved experi- 

 mentally that the conidia germinate easily in water, that the 

 germ-tubes penetrate into living lupines, and produce a mycelium 

 which spreads through stems and leaves to develop strornata on 

 all the organs of the plant. The formation of both pycnidia and 

 conidia goes on throughout the autumn and following spring on 

 dead plants, the fungus being capable of living as a saprophyte 

 and of hibernating. The disease may occur with great severity. 

 Fischer describes cases where more than the half of the plants in 

 a field were attacked and died before flowering or soon after. 

 There is thus a loss not only in lupine seed, but also in the good 

 effects which the crop has as a " green manure." 



Fischer gives the following measures for keeping this pest 

 in check : " Where the fungus has obtained a footing, lupines 

 should not be planted till at least the year after next, and then 

 only as a catch-crop on stubble : it would be still safer to keep 

 lupines off the land till the third or fourth year. After lupines 

 as a catch-crop, they may safely be sown again in spring as a 

 seed crop, after the lapse of a clear year, ^o lupines should 

 be cultivated near diseased fields. Instead of ploughing-in a 

 catch-crop of lupines directly, it should be dried and used as 

 litter for cattle, because the excrement has been found to kill 

 the fungus ; the lupines after lying over winter in the manure- 

 heap could then be used as manure in spring. Similarly when 

 the lupines have been grown for seed, they should be closely 

 mowed down so that little stubble is left ; the straw may then 

 be used for litter." 



This fungus has not as yet been observed on plants other than 

 lupines. 



DlDYMOSI'ORAE. 



Didymosporium. 



Conidia brown, oval or spindle-shaped, bicellular, and not 

 produced in chains. 



Didymosporium salicinum Vuill. Vuillemin reports this as 

 very destructive to the Osier cultivation in Bourgogne. 



Marsonia. 



Conidia transparent, two-celled, and not produced in chains. 

 The species live on leaves. 



