L5 1 PI I 'IMA 



28. Puccinia Taraxaci Plowr. 



Puccinia Phaseoli vax. Taraxaci Etebent. Fl. Neomarch. j>. 356. 



/'. variabilis <!rev. ; Cooke, Handh. p. 500 ; Mier. Fung. p. 207 p.p. 

 /'. Taraxaci Plowr. Ured. p. 180. Sacc. Syll. ix. 305. Sydow, 

 Monogr. i. 164. Fischer, Ured. Schweiz, p. 2-2G, f. 178. 



Spermogones. In little yellow roundish clusters. 

 Uredospores. Sori amphigertous, with or without spots, 

 scattered, minute, sometimes confluent and larger, roundish or 



oblong, pulverulent, brown; spores glo- 

 bose to ovate, echinulate, pale-brown, 

 22 — 27 x 16 — 24 /a, with two germ-pores. 

 Teleutospores. Sori similar, but 

 blackish, h — f mm. diam. ; spores ellip- 



Fig 106. p Taraxaci so ^ to ova ^ e J rounded at both ends, not 

 Teleutospore and uredo- thickened above, not constricted, very 



delicately verruculose, brown, 25 — 38 x 

 16 — 24 fi: epispore thin; pedicels hyaline, short. 



On Taraxacum officinale. Rather common. Spermogones 

 and primary uredospores in April ; the teleutospores may be 

 found till November. The distinctions which Plowright attempts 

 to draw between the primary and secondary uredospores are 

 not so marked as is the case in P. Centaureae, and break down 

 in practice. (Fig. 106.) 



This species differs from P. variabilis, with which it was formerly 

 confused, chiefly in the absence of the eecidium. But, in addition to that, 

 the uredospores of P. Taraxaci are far more abundant and the sori more 

 especially found on the upper leaf-surface; the uredospores of P. variabilis 

 are scanty and are usually intermixed in the teleuto-sori. P. Taraxaci is 

 morphologically indistinguishable from P. Bieracii, but culture experi- 

 ments have proved that it cannot be transferred from Taraxacum to the 

 allied genera of the Compositse. 



Plowright's remark {I. c. p. 187) that I considered this species to have 

 "a true eecidium" is a mistake, arising probably from a confusion between 

 it and P. variabilis. 



Distribution : Europe, North America, Japan, East Indies. 



