April 1908.] 



299 



Sups and Exudations^ 



In the latest British Consular Report 

 on the trade of Bahia, the accompanying 

 interesting: particulars are given with 

 reference to this little known rubber 

 tree : — 



The Manitoba of Bahia is a tree which 

 attains to a height of 30 feet and 

 upwards, with a diameter of 2 feet when 

 fully matured in suitable soil. It 

 belongs to the family Exiphorbiacece. 

 Its zone, so far as is at present known, 

 extends from Maranhao to the southern 

 borders of the State of Bahia, and it is 

 found in greatest abundance in the 

 regions adjoining the town of Jiquie, 

 whence its local name. 



The Jiquie Manitoba is undoubtedly a 

 new and distinct species of Manihot, and 

 it must not be confounded with the 

 Manihot of Ceara (Manihot Ulaziovii). 

 The seeds of the Jiquie Manitoba are 

 much larger than those of the Ceara. 



The season for extracting the latex 

 from the Jiquie Manitoba extends from 

 August to March. The latex possesses 

 the valuable quality of coagulating 

 spontaneously when exposed to the air, 

 and it requires no acid nor other 

 artificial coagulant of any kind. It has 

 been found, from experiment, that this 

 tree can be made to yield its latex 

 between the fourth and fifth years from 

 the time of first planting ; but it yields 

 its maximum returns from the age of 

 eight years onwards. 



The planters of Bahia have awakened 

 to the fact that in the cultivation of 

 Jiquie Manicoba they possess a source of 

 much potential wealth. Already several 

 planters have begun to lay down 

 plantations of the tree in question upon 

 a large scale. 



A planter established in the Jiquie 

 district recently prepared a consider- 

 able quantity of rubber obtained from 

 Manitoba trees groAving wild in the 

 neighboixrhood, and despatched it to 

 New York. The consignment was 

 classified in the New York market as 

 being equal to the best Para rubber, and 

 fetched $l - 28 (5s.) per lb.— Agricultural 

 News, Vol, VI., No. 146, November, 1907, 

 p. 383. 



FURTHER NOTES ON THE MANI- 

 COBA SPECIES OF MANIHOT. 



Zimmermann, in " der Pflanzer," Aug. 

 1907, refers briefly to the three species 

 described by Ule, seeds of all of which 

 have now reached German East Africa. 



Aug. Chevalier in the "Journal 

 d'Agriculture Tropicale," Dec. 1907, 

 describes under the Manihot Teissonnieri 

 a tree growing in the Experimental 

 Garden at Camayenne (French Guinea). 



In a note at the en I of his description he 

 remarks that the plant is possibly 

 indentical with M. piauyhensis of Ule, 

 of which only a preliminary account had 

 then been published. From the des- 

 cription now available this 

 actually to be the case. 



R. H. L. 



seems 



VARIATION AND SELECTION 

 IN HEVEA. 



(Abstract by R. H. Lock.) 



Tot he Journal d" Agriculture Tropicale 

 for July, 190/, M. G. Vernet contributes 

 a very interesting article entitled " A 

 study of the Botanical and Physiological 

 Variations of Hevea brasiliensis as applied 

 to the question of Selection." He points 

 out that Hevea is quite remarkably 

 variable in all sorts of different charac- 

 ters. It is therefore excellently adapted 

 to improvement by selection, and it 

 should be possible to fix a number of 

 different types greatly improved in 

 yield and adapted to various situations, 

 although this process will require a con- 

 siderable number of years to carry out. 



The author speaks first ot variations 

 in the botanical characters. These affect 

 the leaves, flowers, fruits, seed— in fact, 

 every organ which can be mentioned. 

 The time of flowering varies consider- 

 ably, and M. Vernet points out that the 

 offspring of the trees which flower 

 earliest are generally unsatisfactory and 

 give a poor yield of latex. 



Of particular interest are the observ- 

 ations recorded upon the variations in 

 the amount of latex yielded by individual 

 trees and in the proportion of caoutchouc 

 contained in the latex. A table is given 

 showing these variations in the ease of 

 six trees tapped on a particular day. 



Volume of Pr o O f P ^^ Dry 

 latex , 1 . rubber 



obtained. J*™»£ per ££. 



lie. c. 39-74% 4,371 gr. 



15 3010 4,524 

 20 39-41 10,998 



16 31-20 4,492 

 4 32 17 1,286 



12 29 23 3,570 



48 2951 14,161 



No. of 

 tree. 



10 



11 



12 

 13 

 14 

 15 

 18 



Thus, although the proportion of 

 rubber contained in the latex varies 

 considerably from tree to tree, never- 

 theless the volume of latex obtained 

 will be a sufficient index of the relative 

 value of a particular tree, if it remains 

 moderately constant throughout the 

 series of tappings. 



< The above table gives, however, very 

 little idea of the absolute variation in 

 yield, The author meutious two treesj 



