428 BASIDIOMTCETES. 



HYPNOCHACEAE. 



Hypnochus. 



The mycelium forms a cobweb-like covering on living or dead 

 parts of plants. The sporophores take the form of superficial 

 coatings composed of club-shaped basidia developed on a felted 

 hymenial layer of fungal tissue. Each basidium gives off two 

 to six colourless smooth-coated spores from fine sterigmata. 

 Some species are parasitic, and cause disease. 



Hypnochus cucumeris Frk.^ In 1882 Frank found at Berlin, 

 on the surface of withering and dying cucumber-plants, greyish 

 coatings of the hymenial layers of this fungus. They occurred 

 principally near the base of the stem, and caused its partial 

 destruction. The symptoms consisted in leaves becoming rapidly 

 yellow from tip to base, and dying off the plant, the lower 

 first. Only cucumbers were attacked, and no further stages 

 could be observed on the killed plants. 



Hyp. solani Prill, et Del.^ Fine grey crusts, consisting of 

 the hymenial layers of this fungus, were found by these investi- 

 gators on potato-plants ; there was, however, no injurious effect 

 on the crop-yield. 



Aureobasidium. 



Aureobasidium vitis Viala et Boyer.^ The cause of a vine 

 disease which has done considerable damage in southern France 

 on several occasions since 1882. The grapes when attacked show 

 spots, then shrivel up, their interior becoming completely per- 

 meated by a colourless septate and branched mycelium. On 

 rupture of the epidermis, a firm yellow tissue emerges, and 

 thereon a hymenial layer is developed. The basidia are thick 

 and club-shaped, with a varying number of short sterigmata ; 

 these give off cylindrical unicellular light-yellow spores slightly 

 curved in shape and with rounded ends. Leaves are also attacked, 

 and fall off after gradually assuming a deep red colour. If 

 this occurs in April, or early in May, the fruit never attains 

 any size. 



'Frank, Hedwigia, 1883; and Berichte d. deutsch. botan. Ges,, 188,S. 

 ''Prillieux and Delacroix, Bulletin de la Soc. mycol. de France, 1891. 

 'Viala and Boyer, Compt. rend. 1891, p. 1148, andxix., 1894, p. 248; Anna!. 

 de I'Ecole nat. d'agric. de Montpellier, vi., 1891. 



