Jan. io, 1914 
An Undescribed Species of Gymnosporangium 
355 
The three types of spores are described in full, and their diagnostic 
character can readily be seen when Gymnosporangium haraeanum is com¬ 
pared with the other two species given in this paper. In Gymnosporan¬ 
gium japonicum and G. chinensis the spores with thick and moderately 
thick colored walls for each species are so similar that the two kinds are 
described as one; therefore, only two types of spores, thick and thin 
walled, are described for each of these two species. G. chinensis and G. 
haraeanum are so closely related that the writer would not publish the 
former as a new species until he had examined the type material of the 
latter. After a careful examination, however, the conclusion was 
reached that the two were distinct, as they differ in certain fundamental 
microscopic characters. These differences are shown in the description 
given of each species. The most marked difference between these two 
species is the position of the germ pores in the colorless thin-walled 
teliospores. In G. chinesis they are plainly apical in the upper cell, while 
in G. haraeanum they are just as certainly situated only at the septum 
in both cells. 
According to Dr. Clinton, the telia of Gymnosporangium chinensis occur 
on the leaves, but in the very meager herbarium material examined by 
the writer they arose between the leaves rather than on them. The telia 
are therefore stated in the above description to be either caulicolous or 
epiphyllous. 
The three types of spores mentioned in the above descriptions are 
usually more evident in herbarium material than in fresh, as the obstruct¬ 
ing colored contents of the spores fade in drying, thus permitting a 
clearer view of the spore walls. 
The value of taking into consideration at least two types of spores, the 
thick and thin walled ones, is very evident when the corresponding kinds 
for each species are compared. For instance, the oval thick-walled 
spores of Gymnosporangium chinensis , with equal cells rounded at both 
ends, are in marked contrast to the ellipsoid, thick-walled spores of G. 
japonicum , with unequal cells sharply contracted at both ends; while the 
long, narrow, linear-oblong, thin-walled spores, with equal cells of G. 
japonicum , are very different from the shorter thin-walled spores, with 
unequal cells of G. chinensis. Again, many of the thick-walled spores of 
G. japonicum are so sharply attenuated at both ends that they become 
trapezoid in shape, while the apical cells often have a distinctly mammil- 
lated apex. Neither of these characters is present in the thick-walled 
spores of G. chinensis . 
Through the kindness of Dr. Shirai the writer has been able to examine 
some of the material of Gymnosporangium japonicum collected in 1900. 
It was probably a part of the material used by him in his inoculation 
experiments with this species. 1 The specimens sent consist of two 
1 Shirai, M. Uber den genetischen Zusammenhang zwischen Rostelia koreaensis P. Henn. und Gym- 
nosporangium japonicum Sydow. Ztschr. Pflanzenkrank., Bd. io, Heft i, p. 1-5, pi. 1-2,1900. 
17073 0 — r 4 - 6 
