PHANEROGAMIC PARASITES 73 



extends its thread-like branches in every direction, and often 

 completely envelopes its host in a dense, tangled mass, which 

 suggests the idea of the plant having been bound together by 

 a matted tangle of red thread. If the host-plant grows in 

 clusters as in the case of furze, nettle, or clover, the parasite 

 passes from one plant to another. 



All our dodders are annuals, hence their reappearance each 

 year depends on seed. 



Clover dodder. This is the commonest species, called 

 Cuscuta epithymum (Murray), or C. epithymnm, var. trifolii^ by 

 some authors. It grows commonly on thyme, furze, ling, 

 broom, lucerne, clovers, and many other wild plants. Mr. 

 Carruthers records an instance where a crop of clover was 

 attacked by dodder. The clover was cut and the diseased 

 plants left to die on the ground. No signs of dodder were 

 observed on a crop of wheat that followed the clover, but the 

 year following, the plough having brought the dodder seed 

 again to the surface, it germinated after lying dormant for a 

 year, and attacked the crop of turnips then growing in the 

 field. The fleshy leaf-stalk and mid-rib of the leaves were 

 chiefly attacked, but not a few of the roots were also attacked 

 on the upper surface. 



Considerable damage is sometimes done to crops of clover 

 and lucerne by this parasite. As a rule the disease appears in 

 scattered patches in different parts of the field, which are 

 clearly indicated at a distance by the sickly greenish-yellow 

 colour of the clover. If the crop is thick on the ground these 

 patches gradually increase in size, and when conditions are 

 favourable the greater part of the crop may become infected. 



Promptitude is necessary in combating this disease. If the 

 diseased patches are dealt with at an early stage before the 

 dodder has scattered its seed, not only will the spread of the 

 pest be checked, but the land will also be kept free from 

 dodder seed, which would probably attack future crops. The 

 most certain way of doing this is to cut off the clover close to 

 the ground from diseased patches, taking care to remove all 

 plants infected by the parasite. The cut clover should be 

 removed at once and burned. If left about, put on the 

 manure heap, given as food to cattle, a risk is incurred. If 

 delay occurs in removing patches of diseased clover until the 

 dodder has ripened its seed, the clover should be cut as 

 before and allowed to lie on the ground until it will burn. It 



