JO FUXGI IMPERFECT/ 



radiating spots on the leaves of roses. Darliica fihim with similar 

 spores is a common parasite on the rusts (Uredinales). Septoria, 

 one of the largest genera in the family, has slender filiform or rod- 

 like spores which are either divided into numerous cells by cross 

 septa or are marked with clear dots (guttulate) (/7. j. f. i, 2). 



Among the eighty-seven genera of this family the following leaf 

 parasites can be distinguished by this brief synopsis : 



1. Spores I -celled, ovoid or oblong, hyaline. Phyllosticta. 

 Spores I-celled, ovoid or oblong, fuscous or smoky. 2. 

 Spores 2-celled, hyaline. 4. 

 Spores with transvers septa only, 3-many-celled, oblong or fusiform. 



5- 



Spores muriform, ovoid or oblong ; pycnidia subcutaneous or erumpent. 



Camarosporum. 

 Spores elongate-fusiform, continuous or septate. 6. 



2. Pycnidia smooth. 3. 

 Pycnidia setose. Chaetomella. 



3. Spores large (15-30/^ long) stipitate. Sphaeropsis. 

 Spores smaller (3-10/^ long) scarcely stipitate. Coniothyrium. 



4. Pycnidia on definite discolored spots. Ascochyta. 

 Pycnidia not on definite spots, with a radiate arachnoid subiculum. 



Actinonema. 

 5 Spores smoky or olivaceous, muticous ; pycnidia subcutaneous. 



Hendersonia. 

 Spores smoky or olivaceous, ciliate. Cryptostictis. 



Spores hyaline ; pycnidia subglobose. Stagnospora. 



6. Pycnidia usually on definite spots ; spores usually verj' narrow. 



Septoria. 

 Pycnidia rarely on spots ; spores thickened. Phleospora. 



The remaining genera are mainly saprophytic, growing in simi- 

 ilar situations as the Sphaeriales and like them existing free, im- 

 bedded and erumpent from beneath the bark of stems or twigs, or 

 they may even be imbedded in a stroma. Since the ascus in the 

 Sphaeriales is sometimes a somewhat evanescent structure, it is 

 occasionally difficult in practice to distinguish members of this 

 family from the Sphaeriales. The main structural difference be- 

 tween pycnidia and perithecia is found in the method of bearing 

 the spores directly from the walls in the former and in distinct 

 asci in the latter ; usually by suitable choice of material, however, 



