ON COMPOSITE 



133 



been found (Gibson, 1904, p. 188). If that is so, the disease can easily 

 be kept in check by rigid cleanliness and by spraying at intervals with 

 very dilute Bordeaux mixture or, better still, potassium sulphide solution. 

 Remove and burn all attacked leaves as soon as seen, water carefully with- 

 out wetting the leaves, choose resistant varieties {e.g. " October Sun " and 

 " William Tricker" are said to be immune), and there will be little fear 

 of an epidemic of the disease. 



Distribution : Europe, Japan, North America, Australia. 



5. Puccinia Leucanthemi Pass. 



Puccinia Leucanthemi Pass, in Hedw. 1874, p. 47. Sacc. Syll. vii. 705. 



Sydow, Monogr. i. 116, f. 95. 

 P. Asteris var. Chrysanthemi- Leucanthemi Massal. in Bull. Soc. Bot. 



Ital. 1900, p. 258. Sacc. Syll. xvi. 297. Trans. Brit. Myc. Soc. 



iii. 224. 



Teleutospores. Sori amphigenous, generally hypophyllous, 

 often also on the petioles, scattered 

 or often circinate on indistinct spots, 

 or confluent into compact cushions 

 2 — 5 mm. wide, reddish-brown; spores 

 oblong or subclavate, somewhat 

 rounded or more often narrowed at 

 the apex, much thickened above (up 

 to 14 p), constricted, tapering down- 

 wards, smooth, yellowish, 40 — 70 x 

 14 — 24 /x; pedicels hyaline, thick, 

 about as long as the spore. 



On Chrysanthemum Leucanthe- 

 mum. Very rare. Lamorna Cove, 

 Cornwall, September, 1906 (F. J. 

 Chittenden). (Fig. 85.) 



Only recorded for Britain and Italy. The similarity of the spores to 

 the teleutospores of Puccinia JEcidii- Leucanthemi Fisch., which has its 

 eecidiospores on C. Leucantliemuyn and its teleutospores on Carex montana, 

 seems to indicate that this is one of those instances, like P. fusca and P. 

 Pruai-spinosae, which give us a glimpse into the mode of evolution of 

 the Uredinales. 



Fig. 85. P. Leucanthemi. 

 Teleutospores, from an ori- 

 ginal specimen issued by 

 Passerini. 



