1897] MICROSCOPICAL JOURNAL. 371 



opes uredospores on species of Carex; the aecidium fruits 

 of Gymnosporangium caneellata occur only on tlie leaves of 

 the mouutaiii ash and other Pomaceae, the telutospores- 

 only upon those of species of juniper. The aecidiura of 

 the buckthorn is rehited in the same way to Puccinia cor- 

 onata, not uncommon on grasses. Again, the aecidia of 

 the orchid, onion, dock; and dandelion appear in their 

 uredo forms on various grasses and sedges, while the 

 parasites of certain Composites seem to migrate to other 

 plants of the same order. Tlie corn rust, P. riibigo vera^ 

 turns out to be the second stage of an aecidium tiiat grows 

 on the leaves of Anchusa and other plants of the borage 

 family. 



From these examples it will he seen that in fungi of 

 this description each generation of each species has its 

 own form of fructification and its own peculiar host- 

 plant. The brands of the mint and bramble are not het- 

 eruecious, but produce all three sorts of spore on the same 

 host, or even on the same mycelium; the Uredines of the 

 honey-suckle, meadow-rue, and gooseberry, of which only 

 the aecidium forms are known, are likewise restricted to 

 one species of host. In this country^'. grossiUaria only 

 produces aecidiospores; telutospores are stated to have 

 been observed on the gooseberry itself on the Continent, 

 Should this be confirmed, it would appear that the fun- 

 gus in question is confined during its whole existence to 

 to the same plant, and does not, therefore, possess the 

 heteroecismal character. 



In the life history of one of these migratory fungi we 

 have then the following phases: — The earliest form in- 

 habits the leaves of a plant such as the berberry, where 

 it exhausts its eneriges and completes its career by the 

 production and discharge of the aecidiospores; the latter 

 are incapable of germinating on the berberry, but ou 

 being transferred to wheat, at once germinate and form a 

 mycelium which develops the uredo and telutospores. 



