238 FUNGOID PESTS OF CULTIVATED PLANTS. 



are in this instance quite simple, usually depressed and interwoven with 

 the threads of the mycelium. Each of the mature receptacles encloses 

 pear-shaped asci containing eight elliptical uncoloured sporidia. 



This parasite has almost a world-wide distribution, since it is found 

 throughout Europe, in Asia, many parts of America, and in Australia. 



Sacc. Syll. i. 74 ; Cooke, M. F. p. 241, figs. 235, 236 ; Cooke, Hdbk. 

 No. 1926. 



GRASS BLACK BLOTCH. 

 Phyllachora graminis (Pers.), PI. XXIII. fig. 20. 



The leaves of many grasses, whilst still living, are apt to be infested 

 with the black shining blotches of this parasite, the fructification of which 

 does not really mature till the leaves are dead and decaying. 



The spots are mostly oblong, or variable, sometimes confluent, 

 prominent and convex, black and shining with a rough or rugulose 

 surface. The receptacles are immersed in this black stroma, and consist 

 of cells in which the cylindrical asci are closely packed side by side, each 

 containing eight ovoid, simple, and colourless sporidia in a single row 

 (8-12 x 4-5,,). 



Before these asci and sporidia are developed the cells are occupied by 

 curved spermatia (16 x 1^-2/x), which are not produced in asci, but at the 

 apex of short delicate threads. 



Known in Britain, France, Belgium, Germany, Sweden, Finland, 

 Portugal, Italy, Siberia, Cuba, Ceylon, India, North and South America. 



There is no remedy for such a deep seated endophyte, and all efforts 

 must be confined to prevention. It seldom causes any widespread 

 destruction. 



Sacc. Syll. ii. 5132 ; Cooke, Hdbk. No. 2418. 



Similar species are known in Europe on various kinds of grasses, but 

 not yet found in Britain. 



FLOATING GRASS ERGOT. 

 Claviceps Wilsoni (Cooke), PI. XXIII. fig. 21. 



This ergot has been chiefly found on the ovaries of the floating grass 

 Glyceria fluitans, and was discovered by Mr. Stephen Wilson, of Aberdeen, 

 in so far as its ultimate development is concerned. The ergots are smaller 

 than in the Eye, corresponding more with the same kind of ergot on 

 grasses. 



When these ergots germinate, they produce three or four stems, and 

 the heads are usually club-shaped and of a yellowish colour. The recep- 

 tacles are exposed, and nearly free, grouped about the heads, almost 

 bluntly conical in form, and of the same colour as the clubs. As in th& 

 other species the receptacles enclose a great number of long cylindrical 

 tubes or asci, each of which contains eight very long thread-like sporidia. 



Hitherto it has not been recorded out of Britain. 



Sacc. Syll. ix. 4000; Smith, Field Crops, p. 233, figs. 107-111; 

 Grevillea, xii. 77. 



