296 GRIFFITHS: West AMERICAN FUNGI 
Sorosporium Williamsii sp. nov. 
Fungus producing its spores in the peripheral tissues of the 
culm of the host within the leaf sheath, transforming them into a 
black powdery mass and preventing the fructification of the host, the 
upper node being usually but little developed ; two to four nodes 
are commonly involved ; spore mass very loosely united, contain- 
ing many spores, cylindrical, straight or curved, 65-100 X 20- 
304, scarcely distinguishable at maturity ; spores fuscous, sub- 
globose or angular, 5-7 4 in diameter; epispore comparatively 
thin, smooth, but fissured by a few deep grooves which in optical 
section often appear to divide it into four approximately equal seg- 
ments. (Fig. 5.) 
Attacking the sheathed culms of Stipa Richardsoni Link. 
(306), Big Horn Mts., Wyo., August 12, 1896 (T. A. Williams & 
David Griffiths). The species has been collected but once, but 
it was very abundant and destructive in this place, a large pine 
clearing at an altitude of about 8000 feet on one of the tributaries 
of the North Fork of Clear Creek. In habit and gross appearance 
it is identical with U. hypodytes and U. minima. The markings of 
the spores, however, readily separate it from these species even in the 
over-ripe condition when the spore masses have been broken up- 
Gymnoconia riddelliae sp. nov. 
Spermogonia hypophyllous, scattered, prominent, honey-yellow, 
abundant, producing globular* hyaline sporidia 2-3 y in diametet. 
Aecidia amphigenous, but more abundant below, scattered, OF 
cular, oval, or irregular and often confluent over large areas, lilac- 
purple turning to light brown when dry ; spores globular to slightly 
ovate, 7-8 # in diameter, epispore smooth and thin. Uredoson 
amphigenous but more numerous below, circular, small, 0.5 m™: 
in diameter, long covered by the unruptured epidermis which forms 
minute whitish spots not noticeable except under a lens; uredo- 
spores subglobose or angular and often broadly ovate, 20-29 ED 
20-24 y, light brown when mature, the epispore thick, finely 4D 
evenly tuberculate ; teleutospores produced in the same sori aS - 
uredospores and appearing about the time that the epiderm!s rup’ 
tures, the two being mixed for some time, but as the teleutospores 
develop the sori become enlarged, black and very conspicuo’, | 
teleutospores cuneate to elliptical, 38-50 4 x 20-24 / broadly 
rounded or pointed above and conspicuously constricted at | 
septum, epispore smooth, strongly thickened above, the pedic 
(ig. 6) quite persistent, two to three times the length of the spore: 
ig. 6. 
