ON POPLAR 351 
oval to ovate-oblong, 15—22 x 11—16 u; epispore uniformly 
about 2 thick, with two germ-pores(?), echinulate all over; 
paraphyses distributed throughout the sorus, clavate, not capi- 
tate, 40 —50 x 12—17 y, with a uniformly thick wall (3—7 w). 
Fig. 262. M. pinitorqua (from 4 German specimen, ex herb. Sydow). a, a 
young shoot of Pine, in June, with newly-formed leaves, showing three 
ceomata (@), shaded; the leaves have been removed from the affected 
portion, which is beginning to be curved; b, a ceoma, x10; ¢, @ecidio- 
spores; d, old leaf of Aspen, showing numerous teleuto-sori on the lower 
surface ; e, teleutospores. 
Teleutospores. ‘Sori hypophyllous, mostly in clusters, about 
4mm. wide, covered by the epidermis, crust-like, brown, not 
shining; spores prismatic, rounded at both ends, 20—35 x 7— 
11 »; epispore pale-brownish, scarcely 1 » thick, not thickened 
above, without evident germ-pore. 
Ceomata on young shoots of Pinus silvestris which they 
distort, May, June; uredo- and teleutospores on Populus alba, 
P. tremula, and their hybrid (P. canescens), not on P. balsami- 
fera. Rare in this country. (Fig. 262.) 
The connection of the forms on the two hosts was first demonstrated 
by Rostrup and confirmed by Hartig and Klebahn. See p. 57. 
(3) MeELampsora Rostrupi Wagner. 
Uredo confluens DC.; Cooke, Handb. p. 527; Micr. Fung. p. 216, 
pl. 7, £. 133, 134. 
Caeoma Mercurialis Link ; Plowr. Ured. p. 260. Sacc. Syll. vii. 868. 
Melampsora aecidioides Plowr. Ured. p. 241. Sace. Syll. vii. 590. 
M. Rostrupii Wagner, in Oester. Bot. Zeitschr. 1896, xlvi. 273 
Fischer, Ured. Schweiz, p. 501. 
