OPUNTIA 613 



impenetrable and formidable hedge. The fruits are eaten by man, animals, 

 and birds, and the seeds are spread by their agency. The plant thrives on 

 dry barren ground and is amply protected by its spines, and thus it spreads 

 unchecked over waste and forest lands even where there is heavy grazing. 

 To some extent it serves a useful purpose in grazed areas, in affording protec- 

 tion to seedUngs of forest trees, which are able to establish themselves amid 

 the clumps of prickly pear. But any good effect the plant may have in this 

 respect is far outweighed by the harm it does in monopolizing large areas to 

 the exclusion of forest growth and fodder grass. 



Various efforts have been made to eradicate prickly pear over given areas, 

 particularly in Madras, but the process has proved a costly one. Mere cutting 

 or uprooting is of Uttle avail, since the cut pieces, if left on the ground, merely 

 take root and produce new masses of prickly pear. Burying the cut pieces 

 in deep pits has been tried, but even with a covering of earth 1 ft. thick new 

 plants made their way up and the surface of each pit became a dense mass 

 of prickly pear. Stacking the cut pieces on a layer of brushwood and burning 

 them proved more successful, the stacks being left to dry for a few months 

 and then burnt : a few young plants subsequently came up, but they were 

 dug up without difficulty. Mr. A. Lodge has tried poisoning the prickly pear 

 by cutting it into pieces and watering them with a weak solution of arseniate 

 of soda ; the results were quite successful, the pieces turning black and 

 shrivelling up, but the operation was expensive, and the use of a deadly poison 

 necessitated careful supervision. 



It is doubtful if the eradication of prickly pear over extensive areas will 

 be feasible unless some means can be discovered of recouping the cost by 

 providing for its remunerative utihzation. When deprived of its spines it is 

 utilizable as fodder for cattle, though the latter appear to take to it only by 

 degrees. An interesting experiment in burning off the spines and feeding 

 cattle with chopped-up pieces of prickly pear, to which 6 per cent, by weight 

 of cotton seed was added, is described by Messrs. E. W. Horn and S. G. Mut- 

 kekar in the Agricultural Journal of India, vol. ix, pt. ii (April 1914), p. 190. 

 The experiment in question proved decidedly successful, the animals gaining 

 appreciably in weight and condition. A method of burning off the spines 

 with vaporized petrol is described in the Indian Forester, vol. xlii (1916), 

 p. 379 (quoting from the Pioneer). Other possible uses for the prickly pear 

 which have been suggested are the manufacture of alcohol or of paper pulp. 



ORDER XXXIII. RUBIACEAE 



A large and important order, furnishing not only useful timber trees but 

 also trees and shrubs yielding drugs, dyes, and edible products, e. g. Cinchona, 

 Coffea, Morinda, and Rubia. Most of the important timber trees {Antho- 

 cephalus, Adina, Nauclea, and Stephegyne) are characterized by very small 

 light seeds which for successful germination require bare ground devoid of 

 weed-growth, while the minute seedlings are liable to perish in quantity through 

 being washed away by rain ; their reproduction is therefore dependent on 

 somewhat special conditions. 



Genera 1. Anthocephalus, A. Rich.; 2. Adina, Salisb.; 3. Stephegyne, 



