FUNGOID PESTS OF CULTIVATED PLANTS. 145 



GOOSEBEEEY CLUSTER-CUPS. 



Mcidium Grossulance (Gmel.), PI. XII. fig. 33. 



These cluster-cups seem to be rather erratic in their appearance, as in 

 some years they can scarcely be found at all. They occur principally on 

 the living leaves or the green fruit. 



The spots on the leaves are yellow on one side and reddish on the 

 other, with a yellow border. The cups are clustered in the centre of the 

 spots, and are rather long, with the usual white fringed margin. The 

 rccidiospores are bright orange, produced in chains, but freely separating 

 into somewhat globose spores, with a finely spinulose surface (10-20 // 

 diam.). 



This is one of those fortunate species whose fate is not linked with 

 any Uredo or Puccinia. Up to now no enthusiast has imagined for it a- 

 graminivorous bride, and for the present it has to run its course in single 

 blessedness. 



The species is known in France, Belgium, Germany, Lapland^ 

 Denmark, Switzerland, Asiatic Siberia, and North America. 



Quite recently it has been decided by authority that the proper 

 Uredo and Puccinia are to be found on the leaves of species of Carex. 



Sacc. Syll vii. 2787 ; Cooke M. F. 192 ; Gard. Chron. July 1881,. 

 figs. 15-19 ; Mass. PL Dis. 95 ; Cooke Hdbk. No. 1620 ; Plow. Brit. 

 Ured. 263 ; Gard, Chron. May 13, 1905, p. 304, fig. 126. 



GOOSEBEEEY MILDEW. 

 Microspli(zra Grossularia (Lev.), PI. XII. fig. 34. 



A little of the Gooseberry mildew appears every year, but it does not 

 always proceed beyond the mealy or conidial stage. The living leaves 

 become whitened and chalky, as in the allied species, from the interwoven 

 mycelium, which spreads over the surface of the leaves. Its occurrence 

 has been most observed in very dry seasons and on both sides of the 

 leaves. The first stage is an Oidium, with its chain of conidia. 



The receptacles are always few and scattered, being small and globose 

 as usual, and attached to the mycelium by a small bundle of fibres from 

 the base. The circle of appendages which surround the conceptacle 

 consists of from ten to fifteen colourless radiating slender arms, which 

 are forked near the tips, each branch being again forked, and the 

 extremities of all the branchlets split into two teeth, which are pointed, 

 and not thickened as in some other species. 



The contents of the mature conceptacles are from four to eight ovate 

 sacs, or asci, each of which encloses four or five hyaline sporidia, so 

 that each conceptacle may contain from sixteen to forty spores. 



The mycelium of these mildews does not in the first instance establish 

 itself within the substance of the leaves, and never enters to any appre- 

 ciable extent. Hence it is an epiphyte, and has only to be destroyed to 

 restore the vigour of the affected plants. It is in this class of diseases 

 that the application of sulphur is likely to prove most beneficial. 



Sacc. Syll. i. 40 ; Cooke M. F. 240 ; Cooke Hdbk. No. 1922 ; Mass. 

 PI Dis. 95, fig. 15 ; Journ. B.H.S. xxv. (1900), p. 145. 



