HA RD WICKE 'S S CI EN CE-GO SSIP. 



129 



in one whorl, two lower lateral stamens, two upper 

 median stamens, two lateral carpels. Deviations 

 from this type occur from the replacement of each of 



Fig. 109. Diagram of the Cruciferce. 



Axis 



Fig. no. Diagram of Polanisia graveoleiis. 



the upper (inner) median stamens 

 by two or more, through "col- 

 lateral chorisis " ; in the Cruci- 

 ferre usually by two, in the Cleo- 

 mere sometimes by more (figs, 

 109 and no). This " cho- 

 risis " is a branching at an early 

 stage of development, and is 

 rendered probable by the genera 

 Atelanthera and Streptanthus, 

 in the first of which the median 

 stamens are only split, each 

 half-filament bearing a half- 

 anther, whilst in the latter the 

 forked filament bears two entire 

 In the Cmcifer Megacarpaa 

 many members of the section 



Fig. III. Stamen of 

 Streptaiiiluis. 



anthers (fig. in). 

 polyandra, and in 



Cleomese of the allied order Capparidacea?, the 

 stamens are indefinite in number, a condition indi- 

 cated in the genus Crambe, in which each of the 

 four inner stamens puts out a lateral sterile branch. 



G. S. BOULGER. 



THE ECONOMICAL PRODUCTS OF 



PLANTS. 



No. IL 



By J. T. Riches. 



CAOUTCHOUC— This important produce is 

 obtained from many different plants, belonging 

 to totally different natural orders. However, for the 

 present we shall only notice four of the principal 

 plants, distinguished for their superiority in the 

 qualitative and quantitative production of this valu- 

 able article of commerce. 



Fig. 112. Hei'ea [SiplioHia) Brasilienszs [rG^nc^d). «, flower. 



The plants are : — ffdz'ea {Siphonia) Brasiliensis, 

 Mull., Arg., and Castillod dastica, Cerv., natives of 

 the western hemisphere ; and Ficus elastica, Rox., 

 and Urceola dastica, Rox., natives of the eastern 

 hemisphere. 



Commencing with those natives of the western 

 hemisphere, H. Brasiliensis is a native of Guiana, the 

 Amazon and Rio Negro districts of Brazil. The 

 tree has a straight trunk, about sixty feet in height. 

 Leaves on long footstalks, ternate ; leaflets elliptical, 



