Observations on some Scottish Uredineae and Ustilagineae 137 



P. SEPTENTRIONALIS Juel. 



This species is frequently found on the higher Scottish 

 mountains at altitudes from 2000-3500 ft., where the host 

 plants, Thalictriim alpiniim L. and Polygonum viviparum L., 

 grow in association. On the continent the lu-edospore and teleuto- 

 spore stages have also been recorded on Polygonum Bistorta L. 

 This latter species is a typical lowland plant, the greatest altitude 

 at which it has been recorded being 600 ft., while its northern 

 limit is given as Aberdeen — Isle of Skye (Watson, Cybele Britan- 

 nica, vol. 11, p. 332) . Thalictrum alpinum rarely or never descends 

 below 1500 ft. in central Scotland, although it has been found 

 at sea level in the extreme north. It is in consequence highly 

 improbable that P. septentrionalis should naturally occur on 

 P. Bistorta in this country. In order to determine the suscepti- 

 bilitv of the latter species aecidiospores from Thalictrum alpinum 

 were placed on the leaves of P. Bistorta gro\\ing in the Royal 

 Botanic Garden, Edinburgh. In about three weeks typical uredo- 

 sori of P. septentrionalis were produced on the under surface 

 of the leaves. 



It must be concluded, therefore, that the non-occurrence of 

 Puccinia septentrionalis on Polygonum Bistorta in this country 

 is not determined by the immunity of the latter species but by 

 the distribution of the alternative host, Thalictrum alpinum. 



P. Epilobii DC. 



On Epilobium obscurum Schreb. Collected by Miss D. de 

 Watte\-ille, near Kingussie, Inverness. July 1922. 



Up to the present P. Epilobii has only been described on 

 Epilobium pal ustre in this country. The majority of the specimens 

 in the Edinburgh Herbarium, however, including one collected 

 bv Gre\ille in Edinburgh in 1S21, appear to be on E. obscurum. 

 E. obscurum was pre\'iously regarded as a sub-species of E. tetra- 

 gomim, and it is noteworthy that a hybrid exists between 

 E. pal ustre and E. obscurum. P. Epilobii is recorded on E. roseum 

 on the continent but not on E. tetragonum. 



P. GLUMARUM Erikss. et Henn. 



Uredospores and teleutospores on Hordeum murinum L. 

 Collected by Mr M. Y. Orr, Berwick, October 1922, and by 

 Mr G. B. Wallace, Edinburgh and Pathhead, Midlothian, 

 October 1923. 



The rust on Hordeum murinum does not appear previously 

 to have been found in Britain. In the specimens a few uredo- 

 spores are present on the leaves and teleutospores are found 

 on the sheaths; both kinds of spores occur on the glumes. The 

 son are minute and arranged in indefinite Hues. The uredo- 

 spores are verrucose, oval, 20-34 x 18-23 /x, niean 26 x 21 /x. 



