350 



UREDINEAE. 



Stems, leaf-stalks, and leaf-nervature often undergo one-sided 

 thickening and curvature as a result of formation of aecidia. 

 Wakker thus summarizes his observations on the anatomical 

 changes in these malformed parts of Urtica : there is an en- 

 largement of cells and an increase in the number of large inter- 

 cellular spaces; no formation of coUenchyma, interfascicular 

 cambium, and chlorophyll ; a diminished formation of calcium 

 oxalate ; an orange coloration of the cell-sap ; and a distension 

 or rupture of the epidermis. 



Fig. 1S5. — Puccinia caricis on Stinging Nettle. The aecidial cushions have caused 

 swelling and distortion of steins and leaf-stalks, also swollen outgrowths on the 

 leaves, (v. Tubeuf phot.) 



Klebahn and Magnus believe that there is a Puccinia on 

 Carex acuta and G. Goodeiunighii related to an Aecidium on 

 Bibes Grossularia, B. r'uhrwm, and R. aureum ; also a Puccinia 

 on Garex riparia with an Aecidnom on JRibes nigmm. On this 

 account Klebahn^ distinguishes Puce, caricis i., IK, and ill., 

 agreeing respectively with P. PriiigsheiTniana Kleb., P. caricis 

 (Schum.), and P. Magmisii Kleb. 



P. Schoeleriana Plowr. et Magn.^ (Britain). Uredo- and 

 teleutospores on Garex arenaria ; aecidia on Senecio Jacobaea. 



^ Klebahn, Zeitschrift f. Pflanzeiikrankhtiten, 1892, 1894, and 1895. 

 ^ Hedioigia, 1886. 



