ON EPILOBIUM 199 



Puccinia pulverulenta Grew Fl. Edin. p. 432 (1824). Cooke, Handb. 



p. 507 ; Micr. Fung. p. 211, pi. 4, f. 78—9. Plowr. Ured. p. 151. 

 P. Epilobii DC. ; Sacc. Syll. vii. 608 p.p. 

 P. Epilobii-tetragoni Wint. Pilze, p. 214 (1884). Sydow, Monogr. 



i. 424. Fischer, Ured. Schweiz, p. 152, f. 118. McAlpine, Rusts 



of Australia, p. 170, f. 79—81. 



Spermogo7ies. Scattered among the gecidia, honey-coloured. 



sEcidiospores. iEcidia hypophyllous or, when very abundant, 

 also epiphyllous, scattered rather closely over nearly the whole 

 surface of the leaf, cup-shaped, with a white torn revolute 

 margin; spores very delicately verruculose, orange, 16 — -2(j p. 



Uredospores. Sori hypophyllous, scattered or circinate, 

 sometimes confluent, pulverulent, 

 chestnut-brown ; spores globose to 

 ovoid, remotely echinulate, brown, 

 20 — 28 x 15 — 25 fi, with two germ- 

 pores. 



Teleutospores. Sori hypophyl- 

 lous, often circinate, soon naked, 



Fig. 147. P. pulverulenta. Te- 



pulverulent, dark-brown ; spores leutospores and uredospore. 



ellipsoid or ovoid, rounded at both 



ends, somewhat thickened above (up to 5 fi) with a broad low 

 cap-like addition, gently constricted, smooth, brownish, 24 — 35 

 x 14 — 20 fx ; pedicels hyaline, slender, deciduous. 



On Epilobium hirsutum, E. montanum, E. tetragonum. 

 zEcidia, May and June ; teleutospores, June — November. 

 Common. (Fig. 147.) 



The eecidium-forming mycelium appears (but perhaps falsely) to be 

 perennial, for the same plants are attacked year after year. The aecidia 

 appear in May and cover leaf after leaf, as they are developed. The 

 affected plants are easily recognisable by their much paler and yellowish 

 colour. Soon the sori of uredo- and teleutospores begin to appear, at first 

 on the same leaves, but afterwards on the later-formed leaves higher up 

 the plant. In September and October the small last-formed leaves are 

 thickly covered by the teleutospores ; it is probably from the germination 

 of these in spring that the next attack proceeds. The mycelium of the 

 uredo- and teleuto-sori is strictly localised. 



Plowright states (I.e.) that the ajcidiospores sown on young seedlings of 

 E. hirsutum gave rise to aecidiospores in seventeen days, but very possibly 



