84 SUMMARY OF CURRENT RESEARCHES RELATING TO 



identified with any otlier form. K. Hartig has determined it to be the 

 8Bcidioform of Calyptospora Goefpertiana parasitic upon Vaccinium 

 Vitis-Iclcea and Mijrtillus. This last develops its resting spores in 

 the cortical tissue beneath the epidermis of the stem of the host, where 

 they form brown swellings. Young silver-firs and bilberries infected 

 with tlie Gahjptospora were planted in the same pot. The winter- 

 spores of this fungus, when kept moist, put out vigorous promycelia 

 on which si)oridia are developed on delicate sterigmata. These ger- 

 minated on the leaves of the silver-fir ; the germinating filament soon 

 penetrated the tissue, and the golden yellow cushions of fecidia soon 

 made their appearance. A corresponding infection of the leaves of 

 the bilberry with the spores of the aecidium resulted in the same way 

 in the production of the Calyptospora. The development of the 

 spores on the leaves of the silver-fir appears to depend on the occur- 

 rence of several days of rainy weather ; in some years, therefore, the 

 production of the parasite may be entirely suspended. The Calypto- 

 spora is however persistent in the tissue of the Vaccinium. 



Maple-parasite, Cercospora acerina.* — A fungus is occasionally 

 found on the cotyledons of the mountain maple, the mycelium of 

 which penetrates the cells, and protrudes through the epidermis in 

 the form of fertile hyphae with septated conidia curved at the apex ; 

 this passes, by swelling and the division of the cells, the walls of 

 which become black, into a res;ting mycelium, which often retains its 

 power of germinating for a year. Hartig states that it grows also on 

 the soil and in nutrient solutions. The asci have not yet been 

 detected ; it is possible that Sphceria acerina Wallr., found upon 

 dry maple leaves, may be the same species. 



Parasite of Fir-bark, Nectria cucurbitula.| — The fir-trees of 

 Upper Bavaria have been attacked, during recent years, by a fungus 

 which penetrates the bark, chiefly through injuries caused by hail or 

 the weight of snow, or still more, by a microlepidopter, GraplioUiha 

 pactolana. Hartig states that the mycelium develops mainly in the 

 sieve-tubes, but also in the cortical tissue, and only in the spring ; 

 its development in summer is arrested by the want of water in the 

 substratum. The fertile layer appears principally near the base of 

 the stem, where there is a more abundant supply of moisture, in the 

 summer and autumn, as cushions, at first white, afterwards reddish, 

 which break through the bark, and detach firstly conidia, and subse- 

 quently red perithecia, the latter probably the result of impregnation. 

 The ascospores are two-chambered, ripen in the winter, and produce 

 on germination a mycelium, on which conidia are again formed in 

 various ways, sometimes directly, sometimes on special shoots. The 

 development of the mycelium and the formation of the conidia can 

 be followed out in a drop of turpentine. The growth of the parasite 

 destroys the bark and cambium ; the tree dying as soon as the 

 mycelium has grown completely round the stem. 



* Unters. fdrstbot. Inst. Munchen, i. (1880) pp. 58-61. See Bot. Centralbl., i. 

 (1880) p. 972. 



t Ibid., pp. 88-108. 



