153 



The N'hangellite exhibited considerable charring on being 

 heated with strong sulphuric acid; and on being heated with 

 strong nitric acid it passed into solution, but a precipitate was 

 thrown down on cooling. 



XXX -AMERICAN RUBBER PLANTS. 



W. B. Hemsley. 



In 1898 a beginning was made in Hooker's Ico)ies Plantanim 

 with the publication of figures and descriptions of American 

 Rubber Plants, partly of authenticated specimens of more or less 

 known species, partly of species believed to be previously mule- 

 scribed. Any notes by collectors respecting the quality of the 

 rubber yielded by the species under consideration were repro- 

 duced. The genera Hevea, Sap/ inn, and Gastittoa have been 

 partially illustrated, and it is intended to continue the series from 

 time to time as circumstances permit. More rapid progress has 

 been prevented by other work. The genus Saplmn, especially, 

 was in a chaotic condition, due in a great measure to the fact that 

 botanists had followed each other in placing a large number of 

 quite distinct species as varieties of Sapiurn biglanduhsum. 

 About a dozen such species have already been figured in the 

 Irones Plant arum, and drawings of the dissections of the 

 flowers of many others have already been made in continuation 

 of the revision. Meanwhile, Dr. J. Huber, of Para, Brazil, has 



H 



wi 



our 



will usefully supplement his excellent synopses. Dr. Huberts 

 u Ensaio d'uma Synopse das Especies do Genero Hevea sob os 

 pontos de vista Systematico e Geographico" appeared in the 

 Boletim do Museu Goeldi for March, 1906, pp. 620 to 651, without 

 illustration of any kind. The same author'^ revision of the 

 species of Sapium was published in the Bulletin de VHerhirr 

 Boissier, 1906, vol. vi., pp. 345 to 364 and 433 to 452, with 



numerous small but critical figures in the text, under the title : 

 " Revue critique des Especes du Genre Sapiurn." When the Kew 

 collection of Sap mm has been critically elaborated in connection 

 with H liber's " Revu« " we shall have some observations to make 



agreement 



Hevea 



Section 1. EuHEVEA, Muell. Arg. Anthers in one whorl of 5. 



1. guayanensis, Aubl. 



2. nigra, Ule. 



Section 2. BI3IPHONIA, Muell. Arg. Anthers in two whorls. 



Series Luteae. Anthers in two incomplete whorls. Inflor- 

 escence yellowish or gray. Buds of the male flowers 



acuminate 



* ^. , * ,t t a (3. luteo. Muell. Arg. 



h Disk of the male flower \ ^ Cl piculata, Muell. Arg. 



rudimentary. | ^ 



cuneata 



