518 Arthur: New species of Uredineae 



Uredo Holwayi sp. nov. 



O. Pycnia hypophyllous, numerous, scattered, inconspicuous, 

 subcuticular, pale-yellow, becoming brownish, frustum-like or 

 sometimes columnar, 80-1 12 // in diameter by 40-70// high. 



II. Uredinia from a limited mycelium, hypophyllous, in two 

 rows, on yellow spots occupying part or all of a leaf, subepidermal, 

 roundish or oval, 0.1-0.3 mm - across, brownish-yellow, dehiscent 

 by a small central orifice, ruptured epidermis not noticeable ; 

 peridium hemispherical, consisting of appressed hyphae, free at 

 the orifice where they are 10-14// in diameter, with walls 3-4/^ 

 thick ; urediniospores borne singly on pedicels, broadly ellipsoid 

 or obovate, 15-19 by 21-26 /i, wall nearly colorless, medium 

 thick, 1.5-2.5//, strongly echinulate below with sharp points 

 1.5-2.5 ft apart, smooth above; pores obscure; contents orange- 

 yellow when fresh. 



On leaves of Tsuga Mertensiana (Bong.) Carr., Glacier, British 

 Columbia, August 13, 1906, E. W. D. Holway. A unique 

 rust for which no genus seems rightly constituted. It is physio- 

 logically an aecium, and possesses a peridium, but cannot be 

 called Aecidhtm because the spores are borne singly on pedicels 

 instead of being catenulate. In gross appearance it resembles an 

 over-mature Peridermium Peckii, which has lost its protruding 

 peridial cells. Its peridium, however, is not made up of distinct 

 cells, as in Peridermium, but of compacted filaments, the ostiolar 

 ends of which resemble paraphyses. The spores show consider- 

 able similarity to those of Kuehneola, and the pycnia also, but are 

 still more like the pycnia of Gymnoconia. From these resem- 

 blances, the subcuticular pycnia, and other structural features, we 

 may conclude that this is a heteroecious form, having Melampsora- 

 like teliospores on some rosaceous host, or a host belonging to 

 some small family. It may be furthermore assumed, in accord- 

 ance with the general relationship pointed out by Tranzschel, that 

 the telia will resemble those of the so-called Chrysomyxa Abietis 

 on Tsuga canadensis, found in Massachusetts, and that the new 

 genus will be closely related to Pucciniastritnu 



Uredo Chaetochloae sp. nov. 



II. Uredinia amphigenous, numerous, oblong to linear-oblong, 

 about 0.1 mm. wide, 0.5-2 mm. or more long, soon dehiscent by 

 a longitudinal rupture, dark cinnamon-brown, ruptured epidermis 



