THE RUSTS OF NOVA SCOTIA. FRASER. 37 1 



The one-celled teliospore with a single apical germ-pore 

 separates this genus from. Puccinia. They are alike in other 

 respects. Though the teliospores and urediniospores are both 

 one-celled in Uromyces they may be easily distinguished, as 

 the urediniospores are always echinulate or verrucose with 

 several germ-pores, while the teliospores are usually smooth 

 (sometimes verrucose) with only one apical germ-pore. The 

 wall of the teliospore is, also, usually thicker. 



Arthur divides this genus chiefly into four as follows: 



Life cycle with all the spore forms ISTigredo. 



Life cycle with pycriia, aecia and telia .... Uromycopsis. 

 Life cycle with pycnia, uredmia and telia . Klebahnia. 



Life cycle with pycnia and telia Telospora. 



The genus is a very large one embracing over 500 species. 



Uromyces Scirpi Burr. 



Nigredo Scirpi (Cast. ') Arth. 



0. Pycnia amphigenous, numerous, scattered, incon- 

 spicuous. 



1. Aecia amphigenous, gregarious, on discoloured spots, 

 short cylindrical ; peridium pale yellowish, the margin lacerate, 

 recurved. Aeciospores globoid or broadly ellipsoid, 16-21 by 

 18-24/A; wall colourless, thin, minutely verrucose. 



II. Uredinia amphigenous, elongate, remaining covered 

 for some time by the epidermis. Urediniospores mostly 

 ellipsoid, 16-23 by 22-40/*; wall light brown, sparingly 

 echinulate, pores 3 or 4, equatorial. 



III. Telia amphigenous, oblong or linear, long covered 

 by epidermis, compact, brownish-black. Teliospores fusoid or 

 clavate ellipsoid, 17-22 by 33-46jM, rounded at the apex, some- 

 times conical; wall light brown, thickened at the apex to 8/*; 

 pedicel firm, hyaline, or light brown, equalling or longer than 

 the spore. 



