46 
MILDEWS, RUSTS AND SMUTS 
Mierosphaera grossulariae, Lev. Mycelium often soon 
disappearing, or more or less persistent on the upper sur¬ 
face of the leaves ; perithecia scattered or crowded, variable 
in size, 6o—130 [a ; appendages 5—22, i—if times the dia¬ 
meter of the perithecium in length, tips 4—5 times closely 
and regularly forked, branches of the first and second 
orders very short, tips of the ultimate branches not re¬ 
curved ; asci 4—10 ; spores 4—6, rarely only 3, variable 
in size, 20—28 X 12—16 la. 
Syn. Podosphaera grossulariae, Quel. 
Parasitic on the leaves, rarely on the fruit, of the goose¬ 
berry {Rihes grossularia). Sometimes proves injurious, 
causing the leaves to die and fall early in the season, it is, 
however, not nearly so injurious as the American gooseberry 
mildew, Sphaerotheca mors-uvae. 
Mierosphaera mougeotii, Lev. Mycelium effused, thin, 
more or less persistent ; perithecia usually on the upper 
surface of the leaves, somewhat gregarious or scattered, 
115-—170 (a diam. ; appendages very numerous, densel}/ 
crowded, 2—3 times forked at the tip, branching loose, 
irregular and spreading, ultimate branchlets not recurved ; 
asci 10—18 ; spores 2, 20—24 x 12—15 ja. 
Syn. Mierosphaera lycii, Sacc. and Roum. 
Distinguished from all other species of Mierosphaera in 
the densely crowded, widely spreading branches of the tips 
of the appendages, and the 2-spored asci. 
Parasitic on the leaves of the so-called " Tea-tree,” 
Lyeium harhatiim, amd on other species of Lyeium. 
Mierosphaera haumleri, P. Magn. Mycelium soon dis¬ 
appearing, or more or less persistent, mostly on the under 
surface of the leaves ; perithecia in crowded patches, 
80—150 [a diam. ; appendages 8—20, 4—6 times as long 
as the diameter of the perithecium, soft, and forming a tuft 
when mature, tip about 3 times forked, branching loose, 
irregular, ultimate branchlets not recurved ; asci 4—12 ; 
spores 4—8, 20—22 X 10—12 [a. 
Syn. Mierosphaera marehiea, P. Magn. 
Parasitic on leaves of Vieia sylvatiea. 
This is our rarest species included in the Erysiphaceae. 
It has only been recorded once, being detected by Salmon, 
in the Kew herbarium, called Erysiphe eommunis, on Vieia 
sylvatiea, from Scotland. 
