MELAMPSOHA. 



369 



and cause great damage. The yellow 

 sori appear in large numbers on the 

 lower surface of the leaves, which 

 wither prematurely, especially towards 

 the ends of shoots (Fig. 201). The 

 teleutospores hibernate on fallen leaves, 

 hence such should be raked together 

 and burnt. Salix prninosa is found 

 to be much more sensitive to attack 

 than >S'. pruinosa X daphnoidcs, whose 

 leaves are more hairy, a property 

 which seems to protect them from 

 spores. 



The following species have only 

 uredospores and teleutospores, related 

 Cdcom a -ioriw^ being unknown : 



M. lini (Pers.) (Britain and U.S. 

 America). Flax-rust. The uredo- and 

 teleutospores occur together on Linv.m. 

 This may inflict serious damage in 

 tields of cultivated fla.x. 



M. sorbi (Oudem.). On leaves of 

 Pi/rtis Aucuparia and P. torminalis. 

 Dietel ^ has recently placed this as 

 the single species of a new genus 

 Ochrosiwra. The light-yellow spores 

 are at first one-celled, but before 

 the death of the host-leaves they 

 divide into four (rarely three) cells, 

 each of which gives off' a sterigma 

 with a single sporidium. In these 

 points the spores follow the develop- 

 ment of Co/cospormm ; the sporidia, 

 however, are quite different, they are 

 spindle-shaped, 22-2 5^t long and 8/w 

 broad. 



Fic. 201.— .V(r?'/)ii/).<o.'t Htirtlgii on SnlU pruliiom. The upper leaves 

 have already withered and curled up, the lower, though as yet un- 

 changed, are beset with the ix)int-like sori. (v. Tubeuf deL) 



Berichte d. deiUsch. hotan. Gts., 1895, p. 401. 



2a 



