CH. IV 



ALLIES AND ENEMIES 65 



sporophores, or the digging of trenches to prevent the 

 underground spread of the pest. Forest operations 

 should also be carried out with care so as not to injure 

 the trees which are left standing by felling, and thus 

 not to provide ready means of ingress to the spores of 

 injurious fungi. It may be mentioned here, however, 

 that fungi are not all injurious. Many saprophytic 

 fungi carry on a useful mission in destroying dead 

 matter, the superabundance of which would destroy 

 plant life. Some plants even, such as e.g. the Rhodo- 

 dendron, cannot exist without the existence of certain 

 fungi in the soil, and presence of bacteria on roots of 

 leguminous plants has been proved to be of distinct 

 benefit in improving the soil. 



Among the phanerogamous parasites the natural 

 orders of the Loranthaceae and Santalaceae are perhaps 

 the most important to foresters. The former family, to 

 which the mistletoe of Europe belongs, is found also in 

 Asia, Africa, and Australia, and is represented by the 

 genera Loranthus and Viscum, of which the former is 

 the more widely or abundantly distributed. The seeds 

 are distributed chiefly by a bird (Dicaeum). The 

 glutinous seeds remain attached to branches of trees, 

 into the cambium of which they send their roots, and 

 from which they derive their nourishment, or, at least, 

 partly so. Great damage is done to forests in which 

 these parasites establish themselves, and the best 

 remedy is to cut them out ruthlessly. In the arid zone 

 of the Egyptian Sudan, however, the twigs of Loranthus 

 Acaciae are greatly prized by the Arabs for camel- 

 fodder, and, in such circumstances, the sparing of the 

 parasite may be considered. 



Of the Santalaceae the Sandal- wood tree (Santalum 

 album) is the most important, as it yields a wood of 

 great value. It is said to become a root-parasite only 

 after living free for some time, and to attach itself 

 by preference to such trees or shrubs as Cassia 

 auriculata, Lantana, and Casuarina. Among other 

 parasites may be mentioned rootless climbers, such as 



F 



