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MICROSCOPICAL JOURNAL. 



369 



manner bear three kinds of spore on the same host. The 

 rusts of the knot-grass, beet, geranium, and valerian, 

 caused by species of Uromyces, also possess spores of 

 three kinds. Others, like U. alcheniillie and U. rmnicis, 

 have teluto and uredo but no aecidiospores. Only telut- 

 osporeg are known to be produced by the Puccinias para- 

 sitic on the gout-weed, speedwell, mallow, harebell, and 



DESCRIPTION OF THE FIGURES. 

 1. Telutospores: a, Phraginidium violaceum; b, Puccinia menthse; P. 

 violarnm ; d, P. gramiuis. 2. Geimiualing telutospores with promycelia 

 and sporidia : a, Phraginidium ; b, Tiiphragmidium. 3. Uredospores : a, 

 grass blade with rust; b, spores ot bramble rust; c, spores of barren straw- 

 berry; d, e, spores of corn rust; f, of rose rust; g, of thistle rust. 4..^cidia: 

 a, leaf of berberry with cluster cups; b, side view of secidia; c, leaf of sun- 

 spurge spotted with Melamspora; d, clustercups of bedstraw. 5. Spermo- 

 gonia on upper surface of leaf. • 



saxafrage. Uredospores are wanting in the Puccinias 

 of the ragwort and earth-nut; telutospores are absent in 

 the rusts of the figwort and fern, while neither the uredo 

 nor telutospores are known which correspond with the 

 aecidia of honeysuckle, meadow-rue, and gooseberry. 

 The three kinds of spore are not formed simultaneously; 

 further observations may therefore be expected to reduce 

 the number of these exceptions. Before it was known 



