The Scottish Naturalist, 



303 



UredinEjE Tulasne. 



Since the publication of my paper on Heteroecism considerable 

 progress has been made in the only safe course, — (that of careful 

 and continued observation and experiment), — towards a clearer 

 understanding of the true nature of this vexed problem, and of ascer- 

 taining in what genera and species it is a habitual phenomenon. 

 There is still, it is true, much to be done before the question can 

 be considered solved ; but already the labours of numerous myco- 

 logists are reducing the confused mass of details to some degree 

 of order. The genera of Uredineoz in which Heteroecism is known 

 (or at least suspected) to occur in Britain are Uromyces, Puccinia, 

 Gymnosporangium, Melampsora^ and Coleosporium. For the rela- 

 tions of the several forms to one another, and other interesting 

 characters observed during the life-cycle of these and other Uredineae, 

 Mr. Plowrigbt's work, to which reference has already been made, 

 should be consulted as giving the latest views on a confessedly very 

 difficult group. 



The various stages of the fungi are denoted below as follows : — 



0, is the Spermogonium, often produced with the JEcidium. 



1. is the JEcidium stage, whether placed formerly in the restricted genus 

 jEcidium or in an equivalent genus. 



II. is the Uredo stage, formerly ranked under Uredo, Lecythea, Trichobasis i 

 &c, as distinct genera. 



III. is the Teleutosjiore stage, from which the names now used are taken. 



Genus I. Uromyces Link. 

 Subgenus I. Euuromyces Schroter. 



A. AUTEUUROMYCES. 



1. U. Fab8B (Pers.) O, I., II., III., all known to occur on the 

 same host plant. 



II. Trichobasis Fabce Lev., M.S., 1320. 



Tweed, Forth, Tay ! Dee ! Moray. 



III. U. appendiculata Lev., p.p., in M.S., 1270, and also 

 Puccifiia Fabce Link., in Myc. Scot., 1266, p.p. 



Tweed, Forth, Clyde ! Argyle ! Tay ! Dee ! Moray. 

 On Peas ! Beans ! and several Vetches (* Vicia sativa / 

 * V. sepium I * V. Cracca I and *Lathyms pratensis !) in 

 summer and autumn ! On Beans, but rarely. I have 

 observed spores of the Puccinia type intermixed with 

 the abundant Uromyces spores. 



