March, 1910.] 



227 



Plant Sanitation, 



regard to the future life of the 

 tree, to commence the fifth tapping 

 period a year after the initiation 

 of the fourth, should in my opinion 

 be made to depend on an investi- 

 gation of the food distribution in the 

 stem. It would be necessary to sacrifice 

 two or three trees for this purpose, and 

 to get an expert botanist (probably at 

 some experimental station) to make an 

 investigation of the distribution of 

 starch in the wood and bark on the 

 tapping area. If the reservoirs in the 

 wood and bark have been refilled, 

 there can be no objection to the continu- 

 ation of tapping, provided that the 

 latex exuding during the fresh tapping 



period satisfies in quality and quantity 

 all fair demands. If, however, the quan- 

 tity of reserve material in the stem 

 proves to be as yet too small, it will 

 be for the expert to decide how long 

 the tree must be " rested " after the 

 fourth tapping period. These exami 

 nations ought to be repeated " at least- 

 every four years, at the end of each 

 fourth tapping period." It follows that 

 the recent dictum, "a rubber tree 

 which is not being tapped is not a whit 

 better than one which is being judi- 

 ciously tapped," is not in accordance 

 with even our present knowledge, for the 

 judicious tapping involves a drain upon 

 the reserve food in the stem. 



MISCELLANEOUS USEFUL PRODUCTS 



A USEFUL LEGUMINOUS PLANT. 



(Prom the Agricultural Neivs, Vol, 

 VIII., No. 200, December, 1909.) 



In L'Agronomie Tropicale for Septem- 

 ber, 1909, there is an account of a 

 leguminous plant, Tephrosia purpurea, 

 which deals with its suitability for the 

 purpose of keeping down weeds in 

 rubber and coffee cultivation. 



For some time the investigations of 

 physiologists and agriculturists have 

 called attention to the disadvantages 

 of weeding (in rubber and similar culti- 

 vations), but changes of methods in 

 this direction have not been adopted by 

 many planters; few experiments have 

 been undertaken in connection with it 

 in the truly practical sense. 



Interest has, however, been awakened, 

 and experiments with leguminous and 

 other plants have been made to a 

 certain extent everywhere. There have 

 been attempts in many regions, to intro- 

 duce a plant which, while capable of 

 keeping down others which are harm- 

 ful, enriches the soil and does not do any 

 harm to such trees as rubber. According 

 to a planter in the Federated Malay 

 States, Tephrosia purpurea fulfils this 

 purpose admirably. This Tephrosia 

 grows slowly at first, but toward the 

 end of four months it attains the dimen- 

 sions of a small bush ; it then commences 

 to show superiority over other plants. 

 When fully grown it is 9 to 11 feet 

 high. In plantations it forms hedges 

 across which no other plant can pass, 

 and the necessary weeding near the 

 plants costs little. The hedges are suffi- 

 ciently distant to allow the air to circu- 

 late between the trees, and the soil is 

 always well shaded and kept in good 

 29 



physical condition. As for the protected 

 trees, these appear to make as good 

 growth as they do on soil that is com- 

 pletely and regularly free from weeds. 



By growing the plants of Tephrosia 

 in hedges, a better circulation around 

 the roots is assured, and the inspection 

 of the protected plants is facilitated ; 

 other methods of cultivation have their 

 advantages, however, as for example, 

 that iu which each rubber tree is sur- 

 rounded by Tephrosia. 



The plants attain a certain height, 

 and should be cut once or twice a year ; 

 but this development gives them an 

 advantage in combatting lalang and 

 other tall weeds, and as they do not 

 climb, they may be planted without in- 

 convenience near rubber and coffee trees. 

 In addition, Tephrosia purpurea is a 

 plant which enriches the soil, has few 

 natural enemies, is very hardy and 

 propagates itself when it is once estab- 

 lished. 



The account goes on to show how a 

 great saving in the expense of weeding 

 follows the adoption of this plant in 

 rubber cultivations. It may be remarked 

 that several species of Tephrosia are com- 

 mon in the West Indies ; among these are 

 "goat rue" (T, cinerea) and "Surinam 

 poison" (T. toxicaria). Of these, the 

 former is a loosely spreading undershrub, 

 which tends to run along the ground ; 

 stem 1 to H feet long, leaflets £ inch to 

 1 inch long ; flowers about \ inch long, 

 red, appearing in February to June ; 

 pods spreading, with 5 to 10 seeds; found 

 in open spaces, thickets and on the 

 sea-shore. T. toxicaria is an upright, 

 larger plant, with an erect stem about 

 4 to 5 feet high, leaflets 1| to 2 inches 

 long ; flowers 2/3 inch long and over, 

 blue ; pods about 2 inches long. 



