PERIsrclKIKAi:. 181 



Species of fungi iiieliuled in this group are the cause of 

 tliose black, sooty coatings found on leaves fre(|uented l)y green 

 Hy {Aphis) and other leaf-insects. These are purely epiphytic 

 and ■ saprophytic forms which derive nourishment from the 

 "lioney-dew" excreted by the insects.^ They multiply very 

 ra})i(lly, and soon form dark coatings on the upper side of 

 leaves and twigs. Little damage need be feared, since the 

 leaves retain their green colour, and the coating is not enough 

 to stop access of light. Amongst them are species of Cap- 

 iwdium, Meliola, and Apiosporium, as well as the conidial forms 

 Fnriiago, Torula, Antcnnaria. 



The modes of reproduction of these forms are exceedingly 

 varied. According to Zopf- they form: (1) ascocarps; (2) many- 

 celled large conidia ; (o) unicellular, very small conidia ; (4) 

 isolated and clustered conidiophores ; (5) gemmae; (6) buds in 

 a yeast-like manner ; while every fragment of a mycelium can 

 produce a new growth. Any of the species may frequent 

 many various plants, and can pass easily from one host to 

 another. Some of the better-known forms are : 



Capnodium salicinum ]\Iont. (liritain). This occurs on 

 s[H'cies of willow, poplar, hop, and many other plants. 



If it appears early and abundant on hop it may cause 

 considerable damage. {FamiKjo irif/f/ns is a conidial foim). 



C. quercinium Pers. on oak. (U.S. America.) 



C. taxi Sacc, et Roum. on Tr/nis. 



C. foedum Sacc. (spermogonium Horm = Chcdn/i/iovvi forda). 

 On the leaves of oleander. (U.S. America.) 



The genus Apiosporium forms similar sooty coatings. 



A. pinophilum Fuck. This covers with a black coating 

 whole twigs and leaves of silver fir; the needles however retain 

 their green colour completely. (Aiifrnnaria and Torula are 

 fcrms ..f this.) 



A. rhododendri Fuck. ; A. ulmi Fuck. ; and other species. 



Phe cDiiidial form Pellicularia which produces grey coatings on tlie coffee- 

 jtlant is considered among the Hyphomycetes. 



Species of Meliola also produce sooty coatings. 



M. citri Sacc. and M. Penzigi Sacc. occur on Citnts in 



iBiisgen, Der Honhjthau. BioloijUcht Studkn an Pflanzen. .Jena (Fi.scher). 

 -Zopf, "Die Conidienfruchte v. Funiago." Nova wtn, VA. 40. Also: Zopf, 

 Dit Pilze; Tulasne, Select, fum/., tii. 



