215 



in 1 9 1 * ,; 



Arthur: Cultures of Uredineae in 1911 81 



Trisetum last fall which were very badly rusted, and planted in 

 the garden. However, this spring I can see the telia on only one 

 leaf, and that is the Trisetum." Even the rust on the one leaf 

 may have been another species. The evanescent character of this 

 species corresponds to that of Puccinia Eatoniae Arth., having 

 aecia on Ranunculus abortirus from a diffused mycelium and ap- 

 pearing over the whole surface of the leaf early in spring. 



As the rust is now for the first time clearly recognized, it is 

 herewith distinctively named and characterized. 



Puccinia monoica (Peck) n. nom. (Aecidium monoicum 

 Peck, Bot Gaz. 4: 230. 1879.) 



0. Pycnia amphigenous, thickly scattered over large areas, 

 preceding or among the aecia, honey-yellow becoming brownish, 

 sub-epidermal, flattened-globose, 90-160/x in diameter by 60-1 12/x 

 high ; ostiolar filaments 30-90/x long. 



1. Aecia chiefly hypophyllous, evenly and thickly scattered, 

 usually occupying the whole under surfaces of the leaves, cupu- 

 late or short cylindrical, 0.3-0.4 mm. in diameter; peridium whit- 

 ish, the margin erect or spreading, somewhat lacerate, the peridial 

 cells rhomboidal, 29-34^ long, the outer wall /-lOfx thick, striate, 

 the inner wall 3-3.5^ thick, verrucose ; aeciospores globoid, 15-23 

 by 18-25^, the wall colorless, 1.5-2.5^ thick, rather finely ver- 

 rucose. 



II. Uredinia chiefly epiphyllous, somewhat gregarious, oval or 

 oblong, 0.5-1 mm. long, cinnamon-brown, pulverulent; uredinio- 

 spores broadly ellipsoid or obovoid, 19-21 by 24-31^, the wall 

 cinnamon-brown, about 2^ thick, finely and closely echinulate, 

 the pores 6-8, scattered. 



III. Telia chiefly epiphyllous, more or less gregarious, oval, 

 oblong, or roundish, 0.5-1 mm. long, pulvinate, chocolate-brown 

 or cinereous by germination at maturity, early naked ; teliospores 

 ellipsoid or clavate-oblong, 16-24 by 34 - 45A t > the wall cinnamon- 

 brown, 1-1.5/* thick, thicker at apex, 5-10/x, smooth ; pedicel nearly 

 or quite colorless, rather slender, once to twice length of spore. 



O and I. Pycnia and aecia on various species of Arabis throughout the 

 Rocky mountain region, type collection from Colorado, on Arabis retrofracta. 

 made by T. S. Brandegee. 



II and III. Uredinia and telia on various species of Trisetum, the present 

 known geographical range not so great a9 for the aecial stage. 



3. Gymnosporangium Nelsoni Arth. (G. durum Kern), on 

 Juniper us utahensis (Engelm.) Lemmon, sent by Mr. E. Bethel 

 from Delta, Colo., was sown April 5 on Amelanchier vulgaris, 



