i66 Robinson . — Notes on the Genus Taphrina 
of the fruit ; and, lastly, by the swelling and distortion of 
the twigs and young branches. 
In showing in some degree the affinities within the group, 
as well as in furnishing a means of ready determination of 
the individual species here described, the following synopsis 
of the American species which I have been able to examine 
may be found useful. Tulasne, in subdividing his new genus, 
Taphrina , had regard to the lines of division between the 
older genera of which it was composed, and accordingly 
grouped his species into those with so-called polysporic asci 
( 'Taphrina , Fries, and Ascomyces , Mont, et Desm.), and those 
with eight-spored asci (. Exoascus , Fuckel). But, as just stated, 
the polysporic condition is probably secondary, and the spores 
of all the so-called octosporic species are very liable to 
multiply within the ascus. This distinction therefore does not 
seem of primary importance, and in arranging the American 
species it is better to follow Sadebeck and Johanson in 
grouping the species according to the depth to which their 
mycelia penetrate the tissues of the host-plant. It will be 
understood that the following synopsis is not intended to 
be exhaustive, as there are several forms of Taphrina more 
or less perfectly known in America which I have been 
unable to examine. 
Synopsis of American Species examined. 
I. Mycelium penetrating intercellularly the inner tissues 
of the host. 
(1) Fertile portion of the mycelium between the epidermis 
and the cuticle, 
(a) Asci raised on stalk-cells, 
T. Pruni (Fuckel), Tul. 
T. deformans (Berk.), Tul. 
( b ) Asci without stalk-cells, 
T. purpurascens (Ellis et Evh.). 
(2) Fertile portion of the mycelium beneath the epidermis, 
T. Potentillae (Farw.), Johans. 
T. Jlava , Farw. 
