164 Bulletin 313 



Peridermium rostrupi E. Fischer (= Coleospormm campanulce 

 (Pers.) Lev. (See page 159.) 



PoLYTHELis THALiCTRi (Chev.) Arthur. — On Thalictrum sp. 



"O. Pycnia h}^ophyllous, few, sparingly scattered, among the 

 teha, papillose, chestnut-brown, subcuticular, depressed-hemispheri- 

 cal, 110-130 yi. broad. 



"III. Telia h}^ophyllous, evenly scattered, over large areas, 

 never confluent, round 0.2-0.6 mm. across, dehiscent by a pore, early 

 naked, pulverulent, dark, chestnut-brown, ruptured epidermis evi- 

 dent; teliospores ellipsoid or oblong-ovate, 17-26 by 26-52 fjL, greatly 

 constricted at septum, the two cells easily separating, upper cell glo- 

 boid, or rarely elliptical, the lower globoid, obvate or broadly cime- 

 ate, 16-26 by 18-26 /x; wall dark chestnut-bro\\-n, uniformly thick, 

 2 fi, coarsely and evenly verrucose; pedicel delicate, colorless, as 

 long as the spore, wholly or partially deciduous. Mesospores usu- 

 ally plentiful." North American Flora, v. 7, p. 153 (1907). 



937. Lower surface of infected leaf of Thalictrum sp. showing telputo sori. 

 938. Teleutospores, 1/12. 



Phragmidium AiiERiCAXUM Dictel. — On Rosa sp. 



"O. Pycnia chiefly epiphyllous, usually few, gregarious and often 

 confluent, inconspicuous, subcuticular and extending do^vnward be- 

 tween the cells, pale honey -yellow, low-conoidal or discoidal, 80-125 

 fi broad by 30-40 fi high. 



"I. Aecia chiefly hypophyllous or petiolicolous, usually com- 

 pound or confluent, forming sori of irregular outline, 1-5 mm. 

 across, applanate bright orange-yellow fading to pale yellow rupt- 

 ured epidermis usually noticeable; paraphyses rather numerous but 

 inconspicuous, surrounding each individual sorus, erect; not ex- 

 ceeding the height of the spore mass, clavate, 10-20 by 38-50 fi, the 

 wall evenly thin, 1 fi, nearly or quite colorless, smooth ; seciospores 

 broadly ellipsoid or globoid, small, 18-20 by 20-26 /a; wall pale- 

 yellow, rather thin, 1-1.5 fi, finely and closely verrucose with well- 

 separated papillae. 



"II. Uredinia hj-pophyllous, numerous, thickly scattered, round, 

 small, 0.1 mm. or less across, early naked, ruptured epidermis in- 

 conspicuous; paraphyses encircling the sorus, abundant and con- 

 spicuous, strongly incurved, cylindrical or somewhat clavate, 9-13 

 by 30-55 /x, the wall evenly thin, 1 /x or less, nearly or quite colorless, 

 smooth; urediniospores obovate-globoid, small, 15-18 by 18-20 fi; 

 wall pale yellow, thin, 1 fi, rather closely verrucose-echinulate, the 

 pores indistinct, small, scattered, 8 /u, or more." 



