THE DICOTYLEDONES 



1841 



Fig. 1743. — Ricimis communis. Castor Oil Plant. Left, male flower with 

 branched stamens. Right, female flower. {After Baillon.) 



Mallotus phillipinensis, which is found from Ceylon to AustraHa, is of 

 economic importance because Kamala dye is obtained from the capsules. 

 The genus is a large one containing some 120 species and is widely distri- 

 buted in the tropics. Another interesting member of this group is Akhornea 

 ilicifolia of which only female plants are in cultivation. These however 

 produce viable seeds due to the formation of embryos from buds produced 

 from the nucellus around the embryo sac. Macaranga caladifolia is peculiar 

 in that the hollow peduncles are inhabited by ants. 



Mention must also be made of Dalechampia roezliana which is exten- 

 sively cultivated. It has a very complex inflorescence, the whole of which is 

 enclosed in two large outer bracts which are coloured white or pink. On 

 the axis above them is a smaller bract in the axil of which is a three-flowered 

 cyme of female flowers. Above this is the male inflorescence which starts 

 with four bracts, above which are about a dozen male flowers and posterior 

 to them a yellow cushion of rudimentary flowers which may secrete a resin. 

 In Brazil this resin is used by bees to make their nests for which reason 

 bees regularly visit the flowers. 



In the tribe Jatropheae is included the very important genus Hevea, 

 which contains some twenty American species. The most important of 

 these is H. brasiliensis (Fig. 1744), the source of the best Para rubber, which 

 is largely exported from the Amazon valley. Towards the end of the last 

 century seedlings were introduced into Ceylon and from there to Malaya, 

 thus gradually diverting the rubber industry to that part of the world. 

 The tree is a large one, usually with a long straight trunk from which the 

 latex is obtained by tapping. We shall refer in detail to the process of 

 extracting this latex in Volume IV. Several other genera of the Euphor- 

 biaceae yield caoutchouc from which rubber can be prepared and we may 



