DEVELOPMENT OF THE PERITHELIUM OF MELIOLA. 
597 
cetes, on the one hand, and the Phycomycetes* ( Mucor, Peronosporece and Saprolegnice) 
on the other: the evolution of the latter group seems undoubtedly attended by a 
fusion of parts before separated—a withdrawal of the sexual organs, so to speak, into 
one another,—and De Bary has followed this out with marvellous skill and success 
in a number of forms passing from Pythium, through the Peronosporece, to certain 
Saprolegnice, in which the male sexual organ (“ antheridium,” “ pollinodium”) is 
normally suppressed. Whether or not we suppose, with De Bary, that the Erysiphece 
took origin from some Peronospovct- like form, it seems reasonable to look upon Meliola 
and its immediate allies as a branch group derived from the Prysiphe stem, either 
from the ancestor of Prysiphe itself or from ancestors which gave rise to Purotium and 
Prysiphe, and that this group has become developed in tropical lands along lines 
more or less parallel to those along which the European forms have proceeded in tem¬ 
perate climates, being, in fact'—-though not in the strictest sense perhaps—“ represen¬ 
tative species.” Be this view entertained or rejected, I am strongly impressed with 
the necessity for further and closer investigation of the very remarkable group of fungi 
centering around or near the Meliola, since they will probably fill up yet more com¬ 
pletely the gap—partially bridged over, it is true—between the lower and higher 
Ascomycetes. 
Description oe Plates. 
Fig. 1. Meliola sp. with portion of epidermis of Memecylon. On the mycelium are 
seta, branchlets, and fruit-bodies in various stages of development.— Zeiss D. 
Fig. 2. Mycelium of another species of the same, found on the leaves of Schutereict 
( Conv .), with portion more highly magnified.— Gundl. ^ and Zeiss D. 
Fig. 3. Portion of mycelium of a species of Meliola on Triumfetta ( Tiliacece ).— 
Zeiss D. 
Fig. 4. Portions of more advanced mycelium of fig. 2 more highly magnified, and 
showing various forms of lateral branchlets.— Zeiss J. 
Fig. 5. Portions of mycelium on Memecylon showing mode of branching and young 
fruit-bodies.— Gundl. and Zeiss D. 
Fig. 6. Vertical section through portion of mycelium where fruit-body is being 
formed. The section is not median.— Zeiss J. 
Fig. 7. End of hypha with three cap-like thickenings and pore-like spot ( haustorium ?) 
seen from below.— Zeiss J. 
Fig. 8. Various forms of seta in plan and elevation.— Zeiss D and J. 
* Vide De Bary, “ Beitr. z. Morph, u. Pliys. cle Pilze,” R. IV., 1881. 
MDCCCLXXXIIL 4 II 
