412 



PROTECTION AGAINST PLANTS. 



perennial. Hops are injurious in osier beds and in alder 

 coppice. They should be dug up. 



6. Parasitic phanerogams, 

 a. Mistletoe (Viscum album, L.). 



This interesting plant lives as a semi-parasite (obtaining 

 carbon from the air, but water, nitrogen, and mineral matter 

 from the sap of its host) on many conifers and broadleaved 

 trees, and chiefly on their branches. The hosts, or trees on 



which it lives, are, most 

 frequently, the apple tree, 

 both wild and cultivated 

 varieties; next, the silver- 

 fir ; frequently, birches, 

 poplars (except aspen), limes, 

 willows, Scots pine, moun- 

 tain-ash, and hawthorn ; 

 occasionally, robinia, maples, 

 horse - chestnut, hornbeam, 

 and aspen. 



It is very rarely found on 

 oaks, but has been observed 

 on pedunculate oak at Thorn- 

 bury, Gloucestershire, and 

 elsewhere in Europe, also 

 on Quercus coccinea, Moench., 

 and Q. palustris, Moench. 

 The alders, beech and spruce 

 appear to be always free from mistletoe, and it very rarely 

 attacks pear-trees. 



It is commoner in Southern Europe than in the North, and 

 is extremely abundant where cider is made. In the N.-W. 

 Himalayan districts, it is frequently found on apricot trees, 

 which are the commonest fruit-trees there. 



Its white berries are eaten by birds, chiefly by the missel- 

 thrush (Turdus visciuorus, L.), and the seeds are either rubbed 

 by the beak against branches of trees, or voided on to them ; the 

 seeds, owing to the viscous nature of the pulp surrounding 

 them, then become attached to the branches. 



Fig. 199. Acer rubrum, L., attacked 

 by mistletoe (?). (Reduced.) 



