288 



TRIPHRAGMIl M 



Spermogones. On the leaves and petioles, circulate, flat, 

 yellowish. 



Uredospores. Sori of two kinds 'primary, i.e. caeomata, 

 amphigrimiis, large, expanded, bright-orange, mostly on the 

 veins and petioles where they cause distortion, without para- 

 physes; secondary, hypophyllous, small, round, scattered, orange, 

 surrounded by paraphyses; spores brilliant-orangt . ellipsoid to 

 obovate, verrucose, 25 — 28x18 — 21 fi, without evident germ- 

 pores. 



Fig. 218. T. Ulmariae. Normal telentospore ; a and b, two abnormal 



ones ; on S. Ulmaria. 



Teleutospores. Sori hypophyllous, small, round, brownish- 

 black, persistent, but pulverulent, sometimes arising in the 

 primary uredo-sori; spores subglobose, flattened, chestnut- 

 brown, more or less rough with obtuse warts, 35 — 49 \i ; each 

 cell has, at a point opposite to the inner corner, a germ-pore 

 round which the warts are often crowded; pedicels colourless, 

 persistent., variable in length: abnormal spores may have two 

 or four to five cells. 



( )n Spiraea Ulmaria, S. Filipendula. Very common on the 



ft inner host. Primary uredospores, May — July ; teleutospores, 

 August — November. (Fig. 218.) 



The primary uredo-sorus may be looked upon as a cseoma, i.e. an 

 recidium, and in any case it corresponds to that developmental stage ; 

 Klebahn proved (Zeitschr. f. Pflanzenkr. 1907) that it is produced by 

 infection by the basidiospores. Dietel observed that, in elevated situations, 

 the secondary uredo-spore generation on S. Ulmaria was almost absent, 

 and the teleutospores arose in connection with the primary uredo-sori ; 

 this is in agreement with the usual shortening of the life-history that 



