506 FUNUI IMPERFKCTL 



2. Sfx't. Didymosporae. 



1. Si(h.-t('ct. Microitcmeae. 



Dicoccum. 



Coiiidia oblong, two-celled, and arising from short simi)le 

 conidiophores. ]\Iycelium subcuticular. 



Dicoccum (Marsonia) rosae (Bon.) causes brown spots on 

 living leaves of roses, and a premature leaf-cast takes place. 

 Little mycelial stromata develop between the epidermal cells 

 and their cuticle, and give off two-celled hyaline conidia. 



D. uniseptatum B. et Br. forms dark patches on twigs of 

 C/citi(ifiH cifdilxi. (Britain.) 



D. lathyrinum Ell. et Gall. On living leaves of Latliyrus 

 ocliivlcucns in America. 



Cycloconium. 



]\Iycelium subcuticular. Conidia one- to three-celled. 



Cycloconium oleaginum Cast.^ When this fungus is present, 

 the leaves of the olive show roundish light-brown spots with 

 dark margins, then becoming discolonred, they roll up and drop 

 off. The mycelium grows in the walls of the epidermal cells, 

 branching dichotomously ; branches of the hyphae break out 

 through the cuticle as sac-like cells, which become the conidio- 

 phores. The conidia consist of one to three cells. Kruch 

 states that Cercospora cladosporioidcs is often present along with 

 this disease of the olive, and may take some part in causing it. 



Peglion states that this or an allied species occurs on leaves 

 of Qucrcus Ilex. 



2. Suhsect. Macronemeae. 



Passalora. 



Conidia oblong or spindle-shaped, two-celled, and borne on tlie 

 apex of greenish pluriseptate conidiophores, arising from an 

 olive-green mycelium. 



Passalora bacilligera M. et Fr. occurs on living leaves of 

 Alnvs (jiiifiiiosd. (Britain.) 



P. microsperma Fuck. This frequently covers the whole 

 lower surface of the leaves of Alnvs incana with little tufts of 



' Knich, Bulh'iin soc. hot. it.a(., 1892. 

 IJoyer, J\'erherr/tes siir leu maladies de VOUvier, Montpellier, 1892. 



