ON CYPERACE/K 



243 



JEcidiospores. /Ecidia hypophyllous, crowded on red and 

 yellow spots, roundish, also in elon- 

 gated clusters on the young branches, 

 petioles, and nerves, sometimes en- 

 tirely covering the young fruits, 

 shortly cylindrical, with broad, re- 

 curved, white, much torn margin ; 

 spores orange, verruculose, 15 — 21 x 

 14—18/*. 



Uredospores. Sori hypophyllous, 

 punctiform, about ^ mm. long, on 

 yellowish spots ; spores more or less 

 globose, pale-brown, echinulate, 18 — 

 22 x 17 — 21 fi, with three, rarely 

 four, germ -pores. 



Teleutospores. Sori amphigenous, linear or punctiform, up 

 to 1 mm. long, pulvinate, brownish-black; spores resembling 

 those of P. Caricis, 40—58 x 15—22 p. 



Fig. 187. P. Pringshe imi 'ana. 

 Leaf of Ribes Grossularia 

 with groups of ascidia. 



^Ecidia on Ribes Grossularia, R. nigrum (?), May and June, 

 common; uredo- and teleutospores on G. acuta, G. caespitosa, 

 G. Goodenovii, G. stricta. (Fig. 187.) 



The teleutospore-hosts are those given by Klebahn and Fischer. 

 Klebahn first suggested the connection of the secidium with a Puccinia on 

 Carex, and has since demonstrated the truth of this idea by many culture 

 experiments. Soppitt also showed the same for Carex acuta and C. Goode- 

 novii. The secidium is said to attack R. alpinvm, R. aureum, R. rubrum, 

 R. sanguineum, but less frequently. Plowright records the secidium on 

 leaves of Ribes nigrum (Norfolk, June, 1890), but there is no proof that it 

 belonged to this species. 



This species is one of those forms originally named by Klebahn 

 P. Ribesii- Caricis ; he has since divided them under five heads which can 

 scarcely be reckoned anything but biological races : — P. Pringsheimiana, 

 P. Ribis- nigri-Acutae, P. Ribis-nigri-Paniculatae, P. Pseudo-cyperi, and 

 P. Magnum (the latter on C. acutiformis and C. riparia). The same 

 species of Ribes serve as alternate hosts in each case, in varying degrees 

 of susceptibility, except that P. Magnusii is not recorded for R. rubrum 

 and R. Grossularia. The morphological differences between these forms 

 are slight and elusive. 



P. Pringsheimiana can be distinguished from P. Caricis by its nearly 



16—2 



