ON POl'LAK 



351 



oval to ovate-oblong, 15 — 22x11 — 16 //.; epispore uniformly 

 about 2 /j, thick, with two germ-pores (?), echinulate all over; 

 paraphyses distributed throughout the sorus, clavate, not capi- 

 tate, 40 — 50 x 12 — 17 fi, with a uniformly thick wall (3 — 7 fi). 



Fig. 262. M. pinitorqua (from a German specimen, ex herb. Sydow). a, a 

 young shoot of Fine, in June, with newly -formed leaves, showing three 

 creomata (a), shaded ; the leaves have been removed from the affected 

 portion, which is beginning to be curved; b, a cieoma, x 10 ; c, recidio- 

 spores ; d, old leaf of Aspen, showing numerous teleuto-sori on the lower 

 surface ; e, teleutospores. 



Teleutospores. Sori hypophyllous, mostly in clusters, about 

 \ mm. wide, covered by the epidermis, crust-like, brown, not 

 shining; spores prismatic, rounded at both ends, 20 — 35 x 7- 

 11 fi ; epispore pale-brownish, scarcely 1 /x thick, not thickened 

 above, without evident germ-pore. 



Cseomata on young shoots of Pinus silvestris which they 

 distort, May, June ; uredo- and teleutospores on Populus alba, 

 P. tremulq, 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) Melampsora Rostrupii Wagner. 



Uredo confluens DC. ; Cooke, Handb. p. .527 ; Mior. Fung. p. 216, 



pi. 7, f. 133, 134. 

 Caeoma Mercurialis Link ; Plowr. Ured. p. 2G0. Sacc. Syll. vii. 868. 

 Melampsora aecidioides Plowr. Ured. p. 241. Sacc. Syll. vii. 590. 

 .1/. Rostrupii Wagner, in Oe.ster. Bot. Zeitschr. 1896, xlvi. 273 



Fischer, Ured. Schweiz, p. 501. 



