PESTS OF THE FLOWER GARDEN. 



399 



three hundred parts of water will destroy the fungus, so long as it is 

 external and has not penetrated deeply into the bulb. 

 Mass. PI. Dis. 325, 441. 



Leaf spots of six different kinds are recorded on Iris leaves in different 

 countries, but none of them have yet been reported as British. 



Gladiolus Smut. 

 Urocystis Gladioli (Smith), PI. V. fig. 94*. 



This smut, which in some respects resembles that of Colchicum, 

 attacks the corms of Gladiolus, forming the spore masses within the 

 corms. These are in rounded balls, or glomerules (40-50 /u diam.) 



The teleutospores, or central fertile spores, are rounded on the outer 

 side, but angular by compression elsewhere : they are dark brown (4-6 ju) 

 and smooth. Externally in the glomerules are a series of colourless 

 sterile spores or conidia, as in most other species of Urocystis, and in this 

 case they are very numerous and evenly distributed. 



The glomerules, or spore masses, have somewhat the appearance of 

 large spores, divided in different directions, but in reality they consist of 

 an agglomeration of smaller spores, closely compressed together into a 

 ball, the inner ones being coloured and capable of germination, the outer 

 series uncoloured and sterile. When fully matured the component cells 

 separate under pressure, but the true function of the sterile cells has not 

 been determined. 



It might be advisable to immerse any suspected corms for a time 

 before planting in Condy's fluid ; but it is hopeless to expect any remedy 

 when the corms are seriously attacked. 



Known also in France and Germany. 



Gard. Chron. Sept. 30, 1876, p. 420, rig. ; Grevillea, v. 57 ; Sacc. 

 Syll. vii. 1900 ; Mass. B.F. 187 ; Ploicr. Br. Ured. 287 ; Cooke M.F. 232. 



Gladiolus leaf-spot (Septoria Gladioli) and Gladiolus rust (Puccinia 

 Gladioli) are at present unknown in Britain. 



Colchicum Smut. 

 Urocystis Colchici (Schl.), PI. V. fig. 94. 



This is a disease of Colchicum which has long been known and too 

 prominent in its manifestations to escape notice. The growing leaves are 

 the subject of attack, and these are distorted and disfigured by the long 

 and ugly pustules formed by the pest. These are large, thick, swollen, or 

 bullate, at first covered by the epidermis, but at length ruptured and 

 fringed with the remains of the torn cuticle, exposing the black, sooty- 

 looking mass of complex spores. 



The glomerules, or clusters, are nearly globose (20-33 x 16-20 /.), with 

 the central spores few and chestnut brown, compressed at the points of 

 contact (10-15 fx). The sterile spores of the circumference are pale, some- 

 times in two strata, and also compressed where they come into contact 

 (7-11 n diam.) When mature the spores are sprinkled about over the 



