352 



MELAMPSOB \ 



Spermogones. Epiphyllous, or a few hypophyllous, in large 

 round clusters, honey-coloured. 



/Eddiuspores. Cseomata hypophyllous and on the petioles 

 and stems, in clusters on pale-yellow spots, often circinate 

 round the spermogones, about 1 mm. wide, often confluent in 

 patches 1 — H cm. wide, bright- orange; spores roundish-poly- 

 gonal or oval, 13 — 18x12 — 10/x: epispore 1 — H n thick, 

 finely and densely verruculose. 



Fig. 263. M. Rostrupii. a, teleutospores on P. tremula ; b, teleutospore on 

 P. alba; c, secidiospoves on Mercurialis perennis; d, paraphyses and 

 uredospores on P. tremula (one paraphysis contains the orange remains of 

 the protoplasm). 



Uredospores. Sori hypophyllous, about 1 mm. wide, pulvi- 

 nate, compact, causing large yellow spots on both sides : spores 

 oval or sometimes roundish-polygonal, 21 — 25x14 — 18 /j. : 

 epispore up to 3/t thick, covered with stout rather distant 

 spines ; paraphyses distributed throughout the sorus, clavate or 

 somewhat capitate, 50 x 15 — 23 fi, with a thick wall (3 — 6 /x). 



Teleutospores. Sori hypophyllous, ^ — 1 mm. wide, scattered 

 over the whole leaf, covered by the epidermis, dark-brown: 

 spores prismatic, rounded at both ends, pale-brown, 40 — 55 x 

 8 — 10 fx\ epispore thin (1 — 2 /a), not thickened above, without 

 any evident germ-pore. 



Cseomata on Mercurialis perennis, April — June; uredo- and 

 teleutospores on Populus alba, P. tremula, and occasionally on 

 other species, September and October. (Fig. 263.) 



The connection of the two forms has been shown by Rostrup, Nielsen, 



I 'low-right, Klebahn, Wagner, and Jacky. The teleutospores may be found 



