HEMIBASIDII. 113 



to germination, there is no fusion of nuclei, and therefore in this " fusion " there 

 is no sexual act. 



Order 1. Ustilaginacese. Conidiophores with transverse walls and lateral 

 conidia. Ustilago (Fig. 99) generally developes its spores in the floral organs 

 of its host-plant, the ovary or anthers, where they arise from hyphae, and form 

 & slimy mass which when mature becomes a black dust. 



To this order belong U. avence, parasitic on Oats, V. hordei and U. nuda 

 {U. jenseni), on Barley; these are the usual cause of " Smut" on cereals. U. 

 Jiypodytes on straw of Elymus and Agropyrum. U. filiformis in the leaves of 

 Glyceria. U. caricis transforms the fruits of various species of Car ex into 

 black, dusty balls. U. violacea developes its violet spore-powder in the anthers 

 of the Caryophyllaceae. U. trugoppgonin, transforms entire inflorescences of 

 Tragopogon into a black-violet mass. Among the largest are U. grandis, which 

 causes the large swollen nodes in the stem of Phragmites, and the Maize Blight, 

 U. tnm/dis, which produces outgrowths about the size of a hand on the spadix of 

 the Maize. 



Order 2. Tilletiaceae. Conidiophores undivided, generally several conidia 

 arise at their apices. Tilletia tritici, the Stinkbiand on Wheat (Fig. 100). The 

 mycelium lives in Wheat-plants, producing its spores in the ovary after the 

 whole interior of this body has been destroyed by the mycelium, with the ex- 

 ception of the external layer of the wall of the ovary, which remains essentially 

 unaltered and encloses the closely packed, firm mass of spores (Fig. 100 d). 

 The grains of Wheat thus attacked are shorter and thicker than the sound ones, 

 and the ears show the presence of this Fungus by their erect position, and 

 the wide separation of the chaff (Fig. 100 a). The unpleasant odour of the 

 ovary prior to the ripening of the spores, has given the name " Stinkbrand," 

 and, in like manner, its hardness when it encloses the ripe spores, is the reason 

 of its beiug also called " Stonebrand." On account of this hardness, the dis- 

 eased grains are readily harvested together with the healthy ones, which become 

 infected by the spores at the threshing. T. lavis (T. fastens) also occurs on 

 Wheat and has smooth brand-spores. 



Entyloma (Fi^. 96), a genus with numerous species, which appear in 

 spots on the leaves of the host-plant, and Tuburcinia (Fig. 98), which makes 

 its appearance on the Primu- 

 laceae, produce white conidia- 

 spots on the surface of the 

 host-plant. The first-named 

 has single spores, the latter 

 has its spores closely massed 

 together. Urocystis (Fig. 101) 

 has its spores surrounded by 

 a number of small and lighter 

 coloured barren spores. U. 

 occulta, Eye-stem Blight, Fi&.lOl. Urocystis. 1, U.coralloides. A spore-ball, 



forms its spores in long magnified 450 times. 2-4, U. anemones: 2-3, brand- 

 streaks in the stems and s P res which are about to terminate (magnified 450 

 .,., T i times). 4, Conidia, the two in a state of fusion, a 



leaves of the Eye, and does third with yacuolea and division-wall, magnified 600 

 considerable damage. U. ce- times. 



