[Crowa Copyruiht lieservecy. 



ROYAL BOTANIC GARDENS, KEW. 



BULLETIN 



Of 



MISCELLANEOUS INFORMATION. 



,No. 



[1915 



L 



THE 



GENUS THESIUM IN SOUTH AFRICA, 



WITH A KEY AND DESCRIPTIONS, OF NEW 

 SPECIES. 



The genus lliesiu/n appears to leacli its Llgliest development in 

 South Africa, and is represented tlicre hy some 128 species, many 

 of which show considerable external similarity. Owing to the 

 unfortunate circumstance that Alphonse De Candolle and AV. 

 iSondcr were working independently on the South African species 

 of the genus and that they both published papers with descriptions 

 of a large number of new species hi the year 1857, whicli ajipeared 

 witliin a few weehs of each otlier, considerable confusion has 

 resulted. Sonder, in a supplementary paper,* and De Cundolle, 

 in the Prodromus, attempted to harmonise the two monographs 

 and to make the necessary reductions uf species, but as the actual 

 types wore not always available to these two botanists, a certain 

 amount of unceitainty has continued to exist. An examination 

 •^^f the type specimens collected by Ecklon and Zeyher, ju'eserved 

 at Stockholm, of the Thunberg specimens from Upsola and of type 

 specimens from the Boissier llerbariuni and from tlie herbaria of 

 the British Museum, Berlin and Vienna, in comparison with the 

 >-pccimcns at Kew, lias ^x^i'^ilted the elucidation of most of the 

 outstanding difficulties. 



In addition to ihe types the wliole of the more modern collec- 

 ions in the heiba?ia at Berlin, Zurich, the Boissier Ilerl^arium, 

 the Bolus TTerbarium and those of Mr, Galpin and Dr. Marloth 

 liuve also been studied and have enabled a fairly comprehensive 



1 



rev 



iew of the s'enus to be undertaken for the Flora Capensfs.f 



iSeveral small pioblems however remain unsolved^ most of 

 which deinaud a careful study of the plants in the field. Some of 

 these are conuectcd with tlte'^pnrasitism of the genus and suggest 

 ijuestions a*^ to the possible effect of the Jtost jdant and other 



* Flura 1857, No. 26, pp. 401- Wr. 



t To ilr. J. Hutchinson, Assisumt for Africa, I am indebtiMl for valuable 

 assistance in the examination of material and tlic preparation of descrip- 

 tioutj of the species. — A.W.H. 



(:mS) 'Wt.2io-im. 1,1:5. 2/15. .T.T..IS. G If. 



