212 BROOKLYN BOTANIC GARDEN MEMOIRS 



in the large size of the urediniospores which are only slightly flattened 

 and are evenly verrucose-echinulate. The teliospores are much longer 

 than those of M. Medusae and are thickened at the apex. The charac- 

 ter of the telial sori suggests that this species may be closely allied 

 to M. albertensis. The sori are much larger as are also both uredinio- 

 and teliospores. 



This species may be the same as that recently cultured by Weir 

 and Hubert (Phytopath. 7: 108. 1917), who used telial material from 

 P. trichocarpa referred to M. Medusae and obtained successful infec- 

 tion on Larix eiiropea and L. occidentalis. The actual material used 

 for infection and the aecia resulting have not been seen by the writer 

 but telial material sent by Dr. Weir from Montana agrees with the 

 form described above. Aecia from the same locality on L. occidentalis 

 agree in general with aecia of Melampsora Medusae and M. Bigeloivii. 

 The walls of the aeciospores are however somewhat thinner, 1-2 fx, 

 and considerably thickened on opposite sides to 3-5 m- They measure 

 17-19 by 19-26 ju. Additional culture work, and a careful comparison 

 of the resulting aecia with those of M. Medusae would be desirable. 

 In any case, the morphological characters of the uredinial and telial 

 stages are considered sufficient to warrant separation. 



19. Melampsora Piscariae sp. nov. 



O. and I. Pycnia and aecia unknown. 



II. Uredinia hypophyllous, scattered, rounded, 0.3-0.5 mm. 

 across, early naked, somewhat pulverulent, orange yellow fading to 

 whitish, ruptured epidermis conspicuous; urediniospores globoid to 

 ellipsoid, 14-16 by 16-19 m; wall colorless, 1.5-2 ix in thickness, finely 

 and closely verrucose-echinulate; paraphyses numerous, intermixed 

 with the spores, capitate, smooth or with an occasional conical echinu- 

 late marking, 32-64 /x long; heads 12-18 /x broad, wall uniformly 

 thick, 2.5-4 M- 



III. Telia not seen. 

 On Euphorbiaceae : 



Piscaria setigera (Hook.) Piper {Eremocarpus setigerus Benth.) — 

 Corvallis, Sept. 20,. 1914, 3308, type. 



Known only from the type locality. 



This species is referred to the genus Melampsora with considerable 

 confidence in spite of the absence of telia, on account of the structure 

 of the sorus, the character of the spores, and the presence of scattered 

 capitate paraphyses. 



20. Melampsorella elatina (A. & S.) Arthur, N. Amer. Flora 7: 



III. 1907. 

 Aecidium elaiinum Alb. & Schw. Consp. Fung. 121. 1805. 



