236 British Urcdinea: and Ustihwinece 



to the foliage of the mountain ash, give rise to the spermogonia in 

 from eight to fifteen days. 



I have failed only twice in thirteen cultures, and I had to experi- 

 ment with material sent from Scotland. Rdthay states (" Spermo- 

 gonien der Rostpilze," 1882, pp. 20-22) that the cecidiospores of this 

 species also occur on Pyrtis aria, mains, and Amelanchier vulgaris. I 

 have applied the promycelial spores to quince {P. vulgaris) in three 

 experiments, to apple {P . mahts) and to beam {P. aria) in one, but 

 without success. 



In the spring of 1884, a patch of spermogonia appeared on a 

 mountain-ash, which had borne the secidiospores in 1883 ; this is the 

 only instance in which I have seen the mycelium of the a^cidiospores 

 survive the winter. Probably this arose from a bud being infected 

 late the previous year. From the fact ot my being unable to produce 

 the aecidiospores on the host-plants with which R^thay succeeded, 

 viz. Pyriis nialns and aria, it is clear that in Europe we have a second 

 species of Gymnosporangium onjuniperus co?ninuiiis, namely G. tre- 

 melloides, Hartig. (Lehrb. d. Baumk, p. 55). 



MELAMPSORA. Castagne. 



Teleutospores unicellular or rarely multicellular from transverse 

 or longitudinal cleavage, in compact flat sori or crusts. Germina- 

 tion by a promycelium, as in Puccinia. Uredospores single, formed 

 on sterigmata. 



The C^omata are considered by many botanists the ascidiospores 

 of this genus. The promycelial spores, when applied to the teleuto- 

 spore host-plant, do not give rise to the uredospores. 



I. MELAMPSORA. 

 Teleutospores formed outside the epidermal cells of the host-plant, and re- 

 maining single. 



Melampsora helioscopise. (Pers.) 

 Uredospores — Sori small, roundish, or irregular, soon pulverulent. 

 Spores elliptical or ovate, finely echinulate, orange-yellow, 

 14-23 X io-i7;u,. Paraphyses abundant, between the spores, 

 capitate, hyaline, 15-18/A broad. 

 Teleutospores — At first deep orange, then blackish brown, rounded, 

 on the stems elongate, scattered. Spores cuneiform, cylindrical, 

 or prismatic, in section polygonal, dark brown, simple, inter- 

 cellular, 30-35 X 12-1S/X.. 



