590 ARTHUR: NEw UREDINEAE . 
The form can not belong to the life cycle of Uropyxis Petalos- 
temonis for numerous reasons. No aecial stage has yet been dis- 
covered for any species of that genus. Should one ever be found, 
it will doubtless have subcuticular pycnia and aecial paraphyses, 
having no true peridium, as occurs in Phragmopyxis, which is 
simply Uropyxis with three-celled teliospores. Beside, U. Petalos- 
temonis is known to have a primary uredo accompanied by pycnia, 
which excludes the likelihood of an aecial stage. Finally both 
from structure and analogy the form may be considered as part of 
some heteroecious grass rust. 
Aecidium fluxum sp. nov. 
O. Pycnia chiefly epiphyllous, few, inconspicuous, subepidermal, 
honey-yellow, subglobose, small, 75~90 in diameter by 66-80 # 
high ; ostiolar filaments long, 80-112 p. 
_ I. Aecia chiefly hypophyllous, few, widely separated in indefi- 
nite groups, short, small, 0.1-o.2 mm. in diameter ; peridium color- 
less, irregularly lacerate, recurved, peridial cells rhomboidal in 
longitudinal section, 27-35 » long, overlapping, outer wall rather 
thick, 5-7 », transversely striate, smooth, inner wall about half as 
thick, somewhat striate, finely verrucose; aeciospores globoid, | 
20-25 in diameter, wall pale-yellow, thin, about I 4, irregularly 
and rather prominently verrucose. 
On Amorpha canescens Pursh, Colorado, 1907, H. L. Shanté, 
communicated by E. W. D. Holway. A delicate and inconspic- 
uous species. It may be remarked that Aecidium Amorphae Cooke 
(Grevillea 6: 137. 1878) is the primary uredo of Uropy*is 
Amorphae (Curt.) Schrét., while the present form is part of a 
heteroecious species, doubtless one of the grass or sedge rusts. 
Aecidium Boehmeriae sp. nov. 
O. Pycnia epiphyllous, few in small groups about 1 mm. across, 
honey-yellow becoming brownish, punctiform, not conspicuous, 
globose or depressed-globose, small, 70-90 in diameter by 50-7 at 
high ; ostiolar filaments up to 6 5 » long. 
I. Aecia hypophyllous, gregarious or sometimes 
groups 2-10 mm. across, on larger discolored spots, short, small, 
about 0.1 mm. in diameter, rather pale-yellow ; peridium colorless, 
margin erose, recurved, peridial cells rhombic, small, 16-23 
long, inner wall medium thin, 3-4 4, moderately verrucose, outer 
wall medium thick, 5~6 yp, striate, smooth; aeciospores & 
in annular 
loboid, 
