Fungous diseases of plants . i^ Fig. 187. Fly .Speck and Sooty Blotch of Apple blotch. Cell fusions and cell aggregations are commonother hand, the specks areat first dense aggregatesof rather light colored hy-phae, and from such specksdelicate hyphae may betraced to similar neighbor-ing spots or to mature speck becomesshining black and the central portionbreaks away and is pre-sumably the source of newinfections. No spore formhas been found accom-panying this phase. Both , ^^ r r 1 Fig. 188. Leptothyrwm Pomi: Develop- types 01 fungus have, ^ „ J ^ ° MENT OF PyCNIDIA FROM P
Fungous diseases of plants . i^ Fig. 187. Fly .Speck and Sooty Blotch of Apple blotch. Cell fusions and cell aggregations are commonother hand, the specks areat first dense aggregatesof rather light colored hy-phae, and from such specksdelicate hyphae may betraced to similar neighbor-ing spots or to mature speck becomesshining black and the central portionbreaks away and is pre-sumably the source of newinfections. No spore formhas been found accom-panying this phase. Both , ^^ r r 1 Fig. 188. Leptothyrwm Pomi: Develop- types 01 fungus have, ^ „ J ^ ° MENT OF PyCNIDIA FROM PyCNOSCLEROTIA however, been followed (Photograph by B. F. Floyd). FUNGI IMPERFECTI 369 throughout the autumn and winter and careful sections made atdifferent times. In the case of the blotch, as the season advances,the cell aggregates may develop a definite sclerotial-like body(November in Missouri). By March this body has differentiatedinto a pycnidium (Fig. 188) 25 to 100/x in diameter, of theLeptothyrium type, bearing hyaline, elliptical spores. The lattermeasure 12-14 X 2-3/^. CHAPTER XIII HEMIBASIDIOMYCETES I. USTILAGINALES Brefeld, O. Die Brandpilze, I. Unters. a. d. Gesammtgeb. *d. Mykologie 5 : I-220. pis. I-13. , O., u. Falck, R. Ibid. 13: 1-75. pis. 1-2. , G. P. North American Ustilagineas. Proc. Boston Soc. Nat. Hist. 31: 329-529. , p. a. Recherches histologiques sur la Famille des Ustilagin^es. Le Botaniste 3 : 240-281. Bary, A. Die Brandpilze. 144 pp. 8 ph. , P. Ustilagineae und Tilletiineae. Natiirl. Pflanzenfam. (Engler u. Prantl, Red.) 1 (Abt. i **): 2-24. figs. de
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