New western species of Gymnosporangium and Roestelia 
FRANK DuNN KERN 
Examination of a large number of specimens of Gymnosporan- 
gium and Roestelia from the Rocky Mountains has .clearly shown 
that there exist in that region several species very unlike any now 
known in the eastern states or in foreign countries. Some of 
these western species are represented in the larger cryptogamic 
herbaria and are labeled with the names of other species, to which 
they have some slight resemblance, or are undetermined. For 
the most part they possess strong diagnostic characters and are 
easily distinguishable from the eastern species, but cultures, to 
supplement field observations, are necessary before the telial and 
aecial forms can be definitely connected. In order that the west- 
€rn species may be properly recognized, and for the sake of con- 
venience in referring to the two stages independently before they 
are connected, the present paper characterizes six new species, 
three of Gymnosporangium and three of Roestelia. Studies of the 
western species in this group have been very materially advanced 
by the co-operation of Professor E. Bethel, of the East Denver 
High School, both through his many contributions of unusually 
fine specimens and through advice and assistance rendered to 
Professor J. C. Arthur and the writer, while on a collecting and 
observation trip in Colorado during the latter part of April and 
first part of May, this year. 
Gymnosporangium Betheli sp. nov. 
Telia appearing on irregular, elongated, gall-like knots varying 
from a few millimeters to several centimeters across, unevenly dis- 
posed, wedge-shaped, 1-1.5 mm. broad by 1-3 mm. long at the 
base by 3-4 mm. high, chestnut-brown, epidermal tissues raised 
and torn about the base ; teliospores ellipsoid, 17-25 by 40-55 p, 
rounded or somewhat narrowed above and below, slightly or not 
constricted at the septum, wall dark cinnamon-brown, varying in 
thickness on different spores, 1-2 2, smooth, pedicel hyaline, cylin- 
drical, uniform, 6-7 » in diameter, very long, pores 2 in each cell, 
near the septum. 
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