312 NORTH AMERICAN FLORA [VOLUME 7 
55. Dicaeoma monoicum (Peck) Arthur & Fromme. 
Aecidium monoicum Peck, Bot. Gaz. 4: 230. 1879. 
Aecidium auriellum Peck, Bull. Torrey Club 10: 74. 1883, 
Aecidium Drabae Tracy & Gall. Jour. Myc. 4:21. 1888. 
Puccinia monoica Arth. Mycologia 4:61. 1912. 
O. Pycnia amphigenous, preceding or among the aecia, thickly scattered over large areas, 
rather prominent, honey-yellow becoming brownish, entirely immersed, flattened-globose, 
90-160 uw in diameter by 60-112 » high; ostiolar filaments 30-90 nx long. 
I. Aecia chiefly hypophyllous, thickly and evenly distributed over large areas, often 
occupying the entire under surface of the leaves, cupulate or short-cylindric, 0.3-0.5 mm. broad; 
peridium pale-yellow or colorless, margin erect or spreading, somewhat lacerate; peridial cells 
oblong or quadratic, 16-24 by 26-37 yu, often abutted and sometimes overlapping, the outer 
wall thick, 7-14 4, smooth and transversely striate, the inner wall thinner, 3-5 p, coarsely 
verrucose; aeciospores globoid or ellipsoid, 15-24 by 17-30 u; wall colorless, 1.5—2.5 » thick, 
finely and closely verrucose. 
On BRASSICACEAE: 
Arabis canescens Nutt., Colorado. 
Arabis connexa Greene, Colorado. 
Arabis Crandallii B. L. Robinson, Colorado. 
Arabis Cusickiit S. Wats., Washington. 
Arabis Drummondii A. Gray (A. oxyphylla Greene), Colorado, New Mexico, Utah. 
Arabis exilis A. Nelson, Montana. 
Arabis Fendleri (S. Wats. ) Greene, Colorado, New Mexico. 
Arabis lignifera A. Nelson, Colorado. 
Arvabis Lyallit S. Wats., Montana. 
Arabis lyrata L., Wisconsin; Ontario. 
Arabis ovata (Pursh) Poir. (A. hirsuta Hook. not Scop.), Colorado, Nevada. 
Arabis platysperma A. Gray, California. 
Arabis retrofracta Graham (A. Kochii Blankinship, A. Holboellii Am. Auct.), Colorado, Mon- 
tana, Utah; British Columbia. 
Arabis Selbyi Rydb., Colorado. 
Arabis Whitedii Piper, Washington. 
Arabis sp., Arizona, Idaho, Minnesota, North Dakota; Manitoba, Saskatchewan. 
Drabasp., New Mexico. 
Phoenocaulis cheiranthoides Nutt. (Arabis Menziesiti Hook., Parrya Menziesii Greene, 
Chetranthus Menziesii Benth. & Hook.), Nevada. 
Phoenocaulis pedicellata (A. Nelson) Heller (Arabis pedicellata A. Nelson), Nevada. 
Schoenocrambe linifolia (Nutt.) Greene (Sisymbrium linifolium Nutt.), Colorado, Montana, 
Utah, Wyoming. . 
Schoenocrambe pbinnata Greene, Colorado. : 
Smelowskia calycina (Desv.) C. A. Mey. (S. americana Rydb.), Wyoming. 
Sophia incisa (Engelm.) Greene (Sisymbrium incisum Engelm.), New Mexico. 
Sophia leptostylis Rydb., Utah. 
Sophia pinnata (Walt.) Howell (Sisymbrium canescens Nutt.), Colorado. 
II. Uredinia mostly epiphyllous, elliptic or oblong-linear, 1~3 mm. long, dark cinnamon- 
brown, early naked, pulverulent, ruptured epidermis conspicuous; urediniospores ellipsoid or 
obovoid, 19-27 by 24-31 y; wall cinnamon-brown, about 2 u thick, closely and finely echinulate, 
the pores 6-8, scattered. 
III. Telia mostly epiphyllous, crowded and sometimes confluent, elliptic or oblong, 
1-3 mm. long, early naked, chestnut-brown or cinerous by germination at maturity, pulvinate, 
ruptured epidermis conspicuous; teliospores ellipsoid or clavate-oblong, 16-24 by 34-55 u, 
usually rounded at both ends, sometimes acute above and tapering below, sfightly or moder- 
ately constricted at septum; wall cinnamon- or chestnut-brown, smooth, 1-1.5 uw thick, 5-10» 
above; pedicel colorless or nearly so, sometimes tinted at attachment, once to twice length 
of spore. 
On POACEAE: 
Koeleria cristata (L.) Pers., Colorado, New Mexico, Wyoming. 
Trisetum spicatum (L,.) Richter (T. subspicatum Beauv. ), Colorado, Utah. 
TypE Locarniry: Colorado, on Arabis retrofracta. . 
DIsTRIBUTION: Ontario and Wisconsin westward to British Columbia and southward to New 
Mexico. 
Exsicceati: Barth. N. Am. Ured. 835, 1164, 1956; Ellis & Ev. N. Am. Fungi 2889a; Garrett, 
Fungi Utah. 75, 194. 
