NOTES ON DIPTEROCARPS. 



No. 5. The Embryo and Seedling" of Balanocarpus 

 maximus, King. 



By I. H. Burkill. 



By the kindness of Dr. F. W. Foxworthy, I have been able to 

 -examine seedlings of Balanocarpus maximus, King. He was so 

 good as to get the fruits for me in the Bikam forest reserve, Lower 

 Perak, on February 1st, 1919, from an old tree which, alone among 

 the trees there, was bearing. The seedlings were raised in the 

 Botanic Gardens, Singapore. 



In the germination of Balanocarpus maximus the fruit-wall 

 splits into three equal parts, one of which carries the placenta 

 attached to it medially. The expanding cotyledons force the seg- 

 ments apart, and immediately increase their gaping if the wall be 

 removed. The equality of these three segments of the fruit-wall 

 suggests Dryobalanops. 



The radicle may essert itself from the fruit through the crack 

 which is opposite the placenta : in figure 1 it is shewn emerging 

 from it. 



Figure 1. A germinating fruit of Balanocarpus maximus, \ nat. size. 

 The embryo, removed from the fruit-wall and seed-coats, is 

 drawn in figures 2 and 3. It is shown in them how the cotyledons 

 are placed so that the outer occupies the apex of the ovary-cavity, 

 ■and the placentar the base. If these two figures be compared 

 with figures of other species of the Dipterocarpaceae, it will be 

 realised that the condition is an extreme one, — a specialisation 

 not attained in any other of the species so far brought under 

 study: and the thought occurs that if, the parental stock of the 

 order possessed an embryo with equal and parallel cotyledons, then 

 this species is most remote from the stock, far more remote than 

 either Balanocarpus penangianus, King, or Balanocarpus Curiisii, 



King, which have been illustrated on pages and of this 



Journal, 1919, No. 81. 



Jour. Straits Branch R. A. Soc, No. 81, 1920. 



