. Fungous diseases of plants, with chapters on physiology, culture methods and technique . apparently stages of the same are almost invariably associated upon the host (Fig. 187), butmay occupy distinct areas upon the same portion of the seem to occur upon the fruit of the apple throughout thelimits of its culture. A sooty blotch and a fly speck are also foundupon the pear, and along a roadside near Columbia, Mo., therewere found more than twenty-five hosts affected by what wasapparently the same fungus. These plants were all woody in tex-ture, and the fungus occurred ge
. Fungous diseases of plants, with chapters on physiology, culture methods and technique . apparently stages of the same are almost invariably associated upon the host (Fig. 187), butmay occupy distinct areas upon the same portion of the seem to occur upon the fruit of the apple throughout thelimits of its culture. A sooty blotch and a fly speck are also foundupon the pear, and along a roadside near Columbia, Mo., therewere found more than twenty-five hosts affected by what wasapparently the same fungus. These plants were all woody in tex-ture, and the fungus occurred generally on the younger twigsand petioles. The forms upon these hosts may be provisionallyreferred to as one fungus. Observation indicates that the organ-ism is most abundant under conditions of considerable moisture,half shade, and abundant dust. The market value of apples isaffected by the discolorations which result. 1 For the material of this account I am very largely indebted to unpublisheddata kindly furnished by Mr. B. F. Floyd of th^ Fla. Exp. Sta. 368 FUNGOUS DISEASES OF PLANTS. The mycelia of both the blotch and the speck are superficial, atmost merely roughening the surface of the cuticle. The blotches are irregular inoutline, sometimescoalescing intolarge areas. Thespecks, as the nameindicates, are small,circular, dark col-ored flecks associ-ated in groups, andsometimes distrib-uted over largeareas. A network of ra-diating olive-brownor fuliginous hyphaemade up of more orless barrel-shapedcells constitute theblotch. Cell fusions and cell aggregations are common. On theother 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. i88. Leptothyrium Pomi: Devel
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