. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 294 FUNGOUS DISEASES OF PLANTS The fungus has been isolated and can be readily grown in artificial media. Upon starchy media, or media containing con- siderable sugar, it produces a very vigorous growth, often cottony in appearance. Glucose agar, corn meal, etc., are colored pink, or some shade of deep red after growth of a week or more; but the color is less intense when the fungus is grown on starchy products, apparently, than on a glucose agar. The fungus. It produces two forms
. Fungous diseases of plants : with chapters on physiology, culture methods and technique . Fungi in agriculture. 294 FUNGOUS DISEASES OF PLANTS The fungus has been isolated and can be readily grown in artificial media. Upon starchy media, or media containing con- siderable sugar, it produces a very vigorous growth, often cottony in appearance. Glucose agar, corn meal, etc., are colored pink, or some shade of deep red after growth of a week or more; but the color is less intense when the fungus is grown on starchy products, apparently, than on a glucose agar. The fungus. It produces two forms of conidia, which have been designated microconidia and macroconidia (Fig. 129). The microconidia are more or less subspherical, or slightly pointed at the base, even pear-shaped, and they are produced by a constric- tion from lateral or terminal branches, the latter being sometimes clustered. Each branch may produce a large number of conidia by successive abscision, and the conidia fre- quently become massed together in balls. They vary from to 8/x Fig. 129. SporotvchvmPo*: Conidiophores . diameter, and are and Conidia ' capable of immediate germination, producing a much branched mycelium. The macro- conidia are far less frequent in culture and in nature than the microconidia. The method of production of the former type is practically the same as in the case of the microconidia. There is, however, greater vacuolation of the protoplasmic contents during the formation of the macroconidia, which, moreover, may become ovoidal, and finally further elongate, becoming once or more septate. They measure x *.. Owing to the fact that the conidia are in general microconidia, properly the type of the genus Sporotrichum, this fungus is retained in that genus. Control. This disease is often one of serious importance in well-arranged and sanitary carnation houses; but it is apparently most to be feared where conditions for forcing the host are desired, or where unsanitary
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