404 PLANT DISEASES 



Spore-mass produced in the ovary, deep brown, with an 

 olive tinge, foetid ; spores globose, elliptical, etc., variable 

 in form and size, averaging 17-21 /x, or 15-26 X 10-15 ft ; wa ^ 

 about 2 fj, thick, pale olive-brown, or sometimes almost 

 cream-colour ; epispore perfectly smooth, 



Tilletia decipiens, Winter, Krypl.-Flora., i. p. in (1884). 

 Spore-mass formed in the ovary, blackish-brown, foetid ; 

 spores globose, irregularly or angularly globose, or broadly 

 elliptical, clear brown, 20-27 /A diam. ; border about 3 /* 

 wide, not appreciably paler ; epispore with raised ridges 

 anastomosing to form an irregular, small-meshed network. 



Urocystis, Rabenh. Sori erumpent, large, black, pulveru- 

 lent; glomerules of one or more large, central, dark-coloured, 

 fertile spores, surrounded by smaller, pale-coloured, sterile 

 spores ; germination as in Tilletia. 



Urocystis colchici, Rab., Fung. Eur., No. 396. Sori 

 black, usually large, elongated ; spore-clusters globose or 

 oblong, 20-33 X 16-20 /*, central spores 2-4, smooth, chest- 

 nut-brown, 10-15 /* diam.; sterile peripheral spores with 

 thickish walls, sometimes arranged in two strata, pale 

 yellowish-brown, 7-11 /x. 



Urocystis cepulae, Frost, Ann. Rep. Mass. Board of 

 Agric., p. 164 (1876-77). Sori forming large black, pul- 

 verulent streaks on the leaves and bulb ; spore-clusters 

 18-25 ju, diam., usually only one dark brown, central, fertile 

 cell, surrounded by numerous small, pale, sterile cells. 



Urocystis occulta, Rab., in Klotzsch Herb. Myc.^ ii. 

 No. 393; Sacc., Syll., vii. p. 515. Forming long streaks 

 on leaf-sheath, leaves, culm, and also in the inflorescence, 

 at first covered by the epidermis, then black and powdery ; 



