pucciNiA. 347 



suppression of secondary vasa, mucilage canals, and calcium 

 oxalate." 



The deformation induced by P. coronata on Ji'/tamnns cathartica 

 was investigated by Fentzling.^ The changes were relatively 

 slight : the parenchymatous cells of the rind were enlarged 

 and separated by large intercellular spaces ; so also the paren- 

 chyma of the bast ; vessels were more numerous in the wood 

 affected ; the epidermal cells in some parts of the leaf were 

 broadened and those of the mesophyll enlarged, abnormally 

 shaped, and with large intercellular spaces ; in diseased leaf- 

 stalks the epidermal cells are thinner-walled and broader, while 

 all parenchymatous cells become enlarged, thinner-walled, and 

 with many intercellular spaces ; the fibro- vascular bundles are 

 enlarged, chiefly from an increase of the wood-parenchyma ; this 

 tissue, in normal petioles, occurs as single rows of cells running 

 radially between the vessels, whereas, in diseased places, three 

 parallel layers of cells may separate neighbouring vessels. 



P. dispersa Eriks. et Henn. Brown-rust. (Britain.) The follow- 

 ing specialized varieties of this species have been distinguished : 



Ser. T. Aecidium on Anchusa arvensis and A. officinalis (Aec. 

 anchusac). 



1. Yav. srcalis on Sccalr ccrmlc- 



Ser. II. Aecidium unknown. (AVhether distinct varieties, 

 somewhat uncertain.) 



2. Var. tritici on Tritlcum vulgarc. 



•^>. Var. hromi on Brvmus arvensis (and Br. hrizacformis). 



4. Xax. arjropi/ri on Triticum repcTis. 

 P. rubigo-vera (D.C.) (P. straminis Fuck., F. striaeformis West.). 

 (Britain and U.S. America.) This, in its uredo- and teleuto- 

 spore stages, frequents various grasses, while the aecidia occur on 

 Boragineae. A variety on species of Hordmm has been designated 

 P. simjylcx. The teleutospore-patches are enveloped in numerous 

 brown paraphyses ; the teleutospores have very short stalks. 



The anatomical changes produced in leaves beset with aecidia 

 have been stated by Wakker as follows : The swelling of the 

 leaf-petioles is due to enlargement of their cells ; the large 

 intercellular spaces of the spongy parenchyma are no longer 



^ Fentzling, I naurniral Dissertation. Freiburg, 1S92. 



-Found along with tlie Aecidium at Montrose (.Scotland) by Prof. .1. W. H. 

 Trail. (Edit.) 



