264 



NATURAL HISTORY OF PLANTS. 



Old World, whose leaves are alternate, imparipinnate, rarely 1-3- 

 foliolate, the polygamous flowers are nearly always trimerous, more 

 rarely with four or five parts. The gamosepalous calyx and the 

 petals, imbricate or nearly valvate, are inserted on a more or less 



Boswellia papyraeea. 



Fig 280. Hermaphrodite flower (f). 



Kg. 281. Longitudinal section 

 of flower. 



Soswellia papyracm. 



concave receptacle, often cup-shaped, more rarely in the form of a 

 deep sac ; this characterises Santiria^ often separated genericaUy 

 from Canarium for this reason. The stamens, generally six in num- 

 ber, and more or less perigynous, are usually free, more rarely mona- 



delphous at the base. The majority 

 of the characters of any importance 

 are therefore most variable in 

 this genus ; but all its species 

 have this ia common, that their 

 fruit is an elongated drupe, often 

 trigonal, with a very thick and hard 

 stone, hollowed into several cells, 

 only one being usually developed, 

 and containiug a seed having 

 a thick oily embryo with entire 

 or cut and contortuplicate cotyle- 

 dons.^ The perigynous nature, that 

 is to say, the concave form of the 

 receptacle, is still more accentuated yd. the Garugas, trees from Asia 

 and Oceania, whose flowers are pentamerous, diplostemonous, 

 having an ovary with four or five cells, and whose fruit is 

 drupaceous, globular, but with many monospermous stones 



Kg. 282. Fruit. 



Kg. 283. Dehiscent 

 firuit. 



■■ Near Canarium is placed Trigonochlamys, 

 incompletely known and having polygamous, 

 trimerous flowers. The sepals are _ very large, 

 valvate; and the petals much shorter and nar- 

 rower. The six stamens, sterile in the female 

 flowers, are inserted on the edge of a smaU con- 



tinuous disk surrounding the gynseoeum. This 

 has a free, glohular, depressed ovary with three 

 hi-ovulate cells. T. Orijiihii is a tree from 

 Malacca, with alternate, compound-imparipin- 

 nate leaves, and ramified inflorescence, azillaiy 

 or terminal. 



