SUPERFICIAL FIX(H. 3*^5 



The Pcrisporiacccc have many })oints in common with the 

 Erysiphacccc, but perithecial a]>pendages are far less common, 

 and in some of the genera there are very typical vegetative struc- 

 tures which are of value in differentiating species. This is 

 especially true of the genus Mcliola, which is very well repre- 

 sented in South .Vfrica. The mycelium is entirely superficial, 

 and each spore, as it germinates, gives rise to a radiating 

 mycelium with small penetrating haustoria ; the hypha; are 'fur- 

 nished with typical outgrowths of two distinct kinds ; the capitate 

 hyphopodia which occur at more or less regular intervals, and 

 are usually two-celled, and the mucronate hyphopodia, which are 

 usually one-celled, and are less plentiful. The latter, w^hich 

 Gaillard* regards as arrested mycelial branches, arc very similar 

 in all the si>ecies, and are of no value in diagnosis. The capitate 

 hyphopodia, which he looks upon as undeveloped perithecia, are 

 of more interest. 



In some species they are opposite, e.g., M. capeiisis on 

 Hippobromus alata, in others alternate, and the terminal cell varies 

 very considerably in form, being either glolx>se or lobed in various 

 wa3's. The erect sterile branches, known as setaj, as also vei'y 

 varied in form, and Gaillard's system of classification is very 

 largely based on their presence or absence, and their form. The 

 majority are simple and straight, or abruptly geniculate at the 

 base, but some are curved in various ways, e.g., M . falcata com- 

 mon on Rubiacea?, and others are branches or forked at the tips; 

 e.g., M. furcilkita and M. varia. 



The iperithecia are similar in form to those of the Erysipha- 

 ceae, but the group with true perithecial appendages is compara- 

 tively small ; in the section without mycelial seta?, however, one 

 frequently finds superficial cells of the perithecium growing out 

 into larvc'eform appendages, e.g., M . pitiggarii^ which occurs oit 

 Rubus and CUffortia. 



In all the forms mentioned the mycelium is filamentous, but 

 a curious species, .1/. peltata, found in the Knysna forest on 

 Podocarpus, shows considerable variation from the usual type, 

 and has certain points df resemblance with a group to be 

 described later, the l'richopeltace?e. When the spore germinates 

 it branches repeatedly, and numerous hypho[x>dia are produced ; 

 the branches become fused by their lateral walls, and as they 

 continue to grow a fiat pseudo-parenchymatous disc is formed, 

 but the course of the comi3oneiit hyphae can easily be traced, and 

 hyphopodia are produced at regular intervals. 



The family Microthyriacecc was composed of very miscel- 

 laneous elements, and it is only owing to the recent work of v- 

 Hohnef and Theissenj; that an intelligible system of classifica- 

 tion has been evolved. The order was limited by them to super- 

 ficial forms, and species which originated below the cuticle were 



* Le Genre Meliola. 

 t Fragm. z. Myk. 



\ Mykologischc Cenfralhhilt. 3 [61. 27^280. Centralhlatt f. Bakf. II 

 Abt. 39, 625. 



