ARTHUR: NEW UREDINEAE 585 
Puccinia praegracilis sp. nov. 
O. and I. Pycnia and aecia not definitely known. 
II. Uredinia amphigenous, scattered, oblong, small, 0.1-0.2 
mm. wide, by 0.2—0.3 mm. long, soon naked, pale-yellow, pulveru- 
lent, ruptured epidermis barely noticeable ; urediniospores broadly 
ovoid, 16-19 x 18-21 p, wall rather thin, about I yp, pale-yellow, 
closely and minutely echinulate, pores about 6, scattered, obscure. 
Ill. Telia amphigenous, oblong or linear, 0.1-0.3 mm. wide, 
by 0.3-1 mm. long, irregularly confluent, covered by the epider- 
mis, purplish-black ; stroma none ; teliospores oblong or linear- 
oblong, 12-13 x 30-42 #4, slightly or not constricted at septum, 
obtuse or truncate at both ends, coronate with short tubercles 
above, wall golden-brown, smooth, thin, 1 #4, somewhat thicker 
above, 2—4 exclusive of tubercles, and darker-colored ; pedicel 
broad, very short, concolorous. 
On Agrostis Thurberiana Hitchc., Glacier, British Columbia, 
1200 meters, September 5, 1902 (type) ; July 29, 1907, BWeD. 
Holway. This species differs in its smaller and more delicate 
uredinio- and teliospores from Puccinia Rhamni (Pers.) Wettst. e, 
coronata Corda), to which it bears considerable resemblance, and 
from other species on Agrostis by the coronate teliospores. Col- 
lections were made at three or four localities, in the same general 
tegion. In each case the rust grew in connection with aecia on 
Limnorchis stricta (Lindl.) Rydb. (Habenaria gracilis S. Wats.), 
and the collector believes the two forms are genetically related- 
The first collection is accompanied by this note: “ This grew ad- 
joining the Habenaria aecidium, and nowhere else. There were 
two localities, one a high meadow where it was quite abundant, 
and another where only a half dozen plants of the Habenaria grew, 
and between these plants the rust was found, the orchid leaves 
still showing the old aecidia.” 
Puccinia Chaetochloae nom. nov. 
The uredinial stage of the species was described in the previous 
paper of this series. Since then the telia have been detected by 
Dr. Bessey in a specimen gathered at Miami, Florida, January 16, 
1907, which makes it possible to transfer the rust to the genus 
Puccinia, Yt may be described as follows : 
Il. Uredo Chaetochloae Arth. Bull. Torrey Club 33: 518, 
1906 
III. Telia amphigenous, few, scattered, oblong or linear, small, 
