34 DISEASES OF TREES 



finds a suitable host-plant, in which case it twines round the 

 stem of the latter and sends numerous absorbing roots, or 

 " Haustoria," into the cortex. Although the root which 

 originally connected the plant with the ground disappears, the 

 dodder nourishes itself by extracting nutritive materials from 

 the host-plant round which it twines by pushing its sucker-roots 

 as far in as the vascular bundles, in which, by breaking up into 

 unicellular threads, they often assume a brush-like appearance. 

 If the plants are small they may soon be killed, but in the case 

 of larger plants it is only their development that is interfered 

 with, and, so far, I have not noticed any appreciable damage to 

 woody plants. 



The Cuscutecz are distributed by means of numerous seeds, 

 which are produced by dense globular inflorescences, situated 

 at some distance apart on the stem ; and it has lately been 

 discovered that the plants themselves may survive the winter. 

 The only protective measure that is practically applicable in the 

 case of this parasite consists in using seed uncontaminated by 

 dodder. At the same time, the eradication of the dodder-plants 

 which are so common along hedges and fences is also to be 

 attended to. These are the places where we most frequently 

 meet with dodder, and there too it will oftenest be found on 

 various woody plants. Cuscuta europcea* the greater dodder, 

 is the species most frequently met with. It is parasitic on 

 almost all trees, as, for instance, Corylus, Salix, Populus, Primus 

 spinosa, but especially on Humulus, Urtica, and Galium. As 

 the lesser dodder, Cuscuta Epithymum, is specially liable to 

 attack clover and lucerne, it is the species most to be feared. 

 Besides having numerous other host-plants, e.g. Thymus, Genista, 

 Calluna, &c., it has also been met with on Vitis. Cuscuta 

 Epilinum is commonest on Linum usitatissimum. The other 

 species are but seldom met with. 



*[C. Europcea is far less common in this country than is the Lesser 

 Dodder, C. Epithymum, and C. Epilinum is not often met with. ED.] 



