184 



trees, considerable variation occurs in tlie shape and size of the 

 seeds from different exaniples, and also in the productiveness of 

 wild trees, among- which ''barren" individuals are sometimes 

 lound. Dr. Cramer gives reproductions of photograi)hs of a series of 

 seeds from trees of //. hrasiliensis growing in the same localities 

 m Brazil, which show striking variation in size. The impossibility 

 of determining critical species from seeds alone is evi^ ' " 

 the author's remark that ''the difference iu [seed] chi._..... .^ 



Hevea Randiana (a closely allied species) and H. hrasiliensis is 

 \es^ marked than may occur between tbp seeds of two trees of true 



hrasiliensis.^^ 



om 



reacnes ot Brazilian rivers, which often overflow their banks at 

 high tide and he suggests an interesting explanation of the cause 

 ot marked differences which are shown in adjacent trees in such 



observed 



rivers from the upper reaches, and these become stranded in quiet 

 corners of the banks, where they form a laver on the water. At 

 ngii tide they are immediately transferred" to a considerable dis- 

 tance on the adjoining banks, where they germinate. Therefore 

 many o± the frees now growing in the lower reaches of Brazilian 

 rivers are really the direct offspring of upper region types, and 

 thus a mixture of the two races has been brought about. 



i^art o of the paper deals with experiments on seedlings and 

 tables and photographs are given showing their relative variation 

 irom dilterent stocks. 



In part 6, Dr. Cramer points out that, according to the late 

 iJr ^ Huber, the Tapajoz region of Brazil whei^e Wickham 



om 



IS at present obtained, and as nearly the whole of the East India 

 plantations have been stocked from seeds gathered in this 



region, it is therefore assumed that the quality of the rubber 

 IS not so_good as it might have been harl the first seeds been 



athered in the Acre district of the up-river regions, i.e., on the 

 em and, other tributaries of the TJoner Mn<1mr« ur^d Pnn'is 



, ^- , , - - — Tipper Madeira and Puriis 



rivers, where the best rubber is at present obtained. There is, 

 however, no indication that this rubber is superior to that which 

 used formerly to be collected in the Tapajoz region. 



ihe question is discussed as to whether this Acre or up-river 

 Hevea m^j be a distinct variety or subspecies of H, hrasiliensis, 

 as is the general belief in Brazil, and Dr. Cramer is himself 

 inclined to this opinion. 



It should be noted that Dr. Cramer's work on Hevea selection 

 so far concerns the character of the seedlings onlv, and it remains 

 to be seen whether the young plants showing ti:ie most vigorou'' 

 grmv-th will prove to give the greatest yield of latex. 



Ur. Cramer s interesting contribution concludes with not«s on 

 the practical maportance of careful choice of the best producing 

 varieties of other agricultural crops, citing as examples the 

 advantages which liave accrued from tfe introduction of 

 ^^ncluma Ledgermna with a bark richer in quinine than the 

 Older offimnalts, the replacement by Assam instead of the old 

 China tea, and the revival of the coffee cultivation in Java by the 

 advent of Coffea rohusta. , ^^ 



