MELA.MPXORELLA 



361 



Fig. 269. M. Caryo- 

 phyllacearum. Peri- 

 dermium elatinum, 

 on A. pectinata 

 (slightly reduced) ; 

 «, a leaf, x 10. 



Melampsora Cerastii Wint. Pilze, p. 242 (1881). Plowr. Ured. p. 217. 

 Melampsorella Cerastii Schrot. Flor. Schles. p. 366 (1887). Sacc. Syll 



vii. 596. 

 M. elatina Arthur, N. Amer. Fl. vii. 111. 



Spenuogones. Epiphyllous, scattered, conical, honey-coloured. 



fficidiospores. iEcidia hypophyllous, arranged in an irregu- 

 lar row on each side of the mid-rib, erumpent, 

 shortly cylindrical, roundish or compressed, 

 pale orange-red, with torn white margin ; 

 spores ellipsoid or polygonal, orange, 16 — 

 30x14 — 17,0.; epispore thin, densely verru- 

 cosa. 



Uredospores. Sori generally hypophyl- 

 lous, usually arising beneath a stoma, sur- 

 rounded by a peridium which slowly opens 

 by an apical pore, small, crowded, pustular, 

 yellow; spores sometimes in short chains, 

 ovoid-oblong or ellipsoid, yellowish, 20 — 30 

 x 16 — 21 fi ; epispore thin, beset with a 

 small number of pointed warts which are 

 only visible when dry, with an occasional glabrous strip (?), 

 without perceptible germ-pores. 



Teleutospores. Hypophyllous, often covering the whole leaf, 

 developed within the epidermal cells, whitish-yellow or pinkish, 

 in little groups in each cell, roundish or flattened, one-celled, 

 14 — 21 fi ; epispore smooth, thin ; basidiospores globose, nearly 

 colourless, 7 — 9 fi. 



yEcidia on leaves of Abies pectinata, June — September; 

 uredo- and teleutospores on Cerastium arvense, C. triviale and 

 its var. alpestre, C. viscosum, Stellaria graminea, S. media 

 (more rarely) ; uredospores from May onwards. Not very 

 common. (Figs. 269, 270.) 



In North America it occurs on other species of Abies, and on Alsine 

 and other species of Cerastium ; also in Europe on numerous allied species 

 of the subfamily Alsinea). The teleutospores are developed on those 

 leaves of the second bost which live through the winter ; they germinate 

 about May ;u id can infect the Silver Fir. There are comparatively few 

 records of the secidium-stage in this country; it causes small erect 



