FUNGOID PESTS OF CULTIVATED PLANTS. 235 



EYE SMUT. 

 Urocystis occulta (Wallr.), PI. XXII. fig. 13. 



This is the Uredo parallela of Sowerby and Berkeley, and occurs 

 principally on the leaves of Bye, but also sometimes on Barley, Wheat, 

 and a few grasses. 



The pustules usually form long streaks on the leaves and stems, and 

 are at first covered by the epidermis and then greyish, afterwards 

 ruptured and then black and powdery. The spores unite in clusters or 

 glomerules, which are globose or elliptical (17-24 x 15-20/*). The 

 central fertile spores, from one to three, opaque brown (12-lS^u diam.), 

 globose or flattened, even. The sterile or peripheral spores, globose or 

 flattened, in an interrupted stratum (4-G^i diam.), pale brown. Fertile 

 spores soon germinating and producing a slender promycelium, bearing at 

 the apex from two to six cylindrical sporidiola. 



Known in France, Belgium, Germany, and North America. 



If the seed grain be immersed for five minutes in hot water (127 Fahr.), 

 it is affirmed that the occurrence of the disease may be prevented. 



Sacc. Syll. xiii. 1891 ; Mass. B. F. p. 185 ; Plowr. Brit. Ured. p. 285 ; 

 Cooke, M. F. figs. 167-188 ; Mass. PL Dis. p. 221, fig. 53 ; CooJce, HdbJe. 

 No. 1540. 



ERGOT OF RYE. 

 Claviceps purpurea (TuL), PL XXII. fig. 14. 



Ergot is a condition of the seeds of the cereals and grasses in which 

 the grain is taken possession of by a fungus, and enlarged or distorted, and 

 converted into a kind of compact mycelium or resting stage, termed a 

 sclerotium. This is best known, as it is most prominent in Eye, but 

 occurs only on Wheat, Barley, and a large number of grasses, and is 

 injurious to animal life. 



An early viscid condition of Ergot has the character of Oidium, and 

 has been called Oidium abortifaciens. 



In Eye the ergot assumes an elongated, black, horn-like form, two or 

 three times as long as the normal Eye seeds, which project from the ear 

 of corn, and they may be kept through the winter, but when placed under 

 favourable conditions of moisture, &c., will germinate in spring. , 



On germination each ergot may produce several bodies with a con- 

 torted stem, and a globose head of a purplish colour. The globose head 

 is dotted with little elevations which indicate the receptacles which are 

 developed beneath. These receptacles or cells contain numerous cylindrical 

 tubes or sacs, termed asci, packed closely side by side. Each of these asci 

 encloses eight long thread-like sporidia (50-76 n long), which are expelled 

 when mature. 



These sporidia, floating in the air when the Eye is in flower, attach 

 themselves thereto, and germinate, infecting the ovary with the virus of 

 the ergot, and developing a new generation. 



It is known in France, Belgium, Germany, Finland, Italy, North 

 America, and Auckland. 



