50 
a supplement to the ‘ Pflanzenreich ’’ monograph, and may serve 
as a guide to the whereabouts of the material which it will be 
incumbent upon the future monographer of the genus to consult. 
History OF THE GENUS. 
The name Chrozophora was applied by Necker in 1790 
(Liem. ii. p. 337) to a monotypic genus based on a plant from 
Languedoc which at that date was the source of one of the 
Litmus dyes known as Tournesol. This name has, indeed! been 
used by most botanists since the XVIth century for the plant 
itself. That plant had been referred by Royen in 1740 (I. 
Lugd. p. 532) to the genus Croton as defined by Linnaeus in 
1737. In 1748 Linnaeus accepted this determination (Hort. 
Upsal. p. 290); it was adopted by his friend and correspondent 
Sauvages in 1750 (Monspel. p. 305) before Linnaeus enumerated 
it, with a definite specific epithet, as Croton tinctorium in 1753 
(Sp. Pl. p. 1004). 
oyen was not the first writer to refer the Tournesol to a genus 
from which it is better kept apart. The plant was well known 
to systematic writers in the XVIth century. ome of these, 
convinced that words connoting the same idea should denote the 
same thing, connected the Tournesol now with one, now with 
another of the plants which the ancients termed Heliotropion. 
Of these the Greeks, according to Dioscorides, knew two sorts— 
ndLoTpOTLoY TO péya, Or SKopriovpov; and mAvoTpoTLov TO juKpoV. 
The Latins, according to Pliny, also knew two—Heloscopium, or 
Verrucaria; and Tricoccon, or Scorpiurum. 
In 1554 Castell-Branco, better known as Amatus Lusitanus 
(Diosc. Enarrat. p. 437), identified the Tournesol of Spain with 
WAoTpoTov To péeya, and repeated this identification with 
some insistence, by including also the Tournesol of France, in 
the larger edition of this work (p. 741) in 1558. This emphasis 
may have been due to the fact that in 1554 both Dodoens (Cruyde- 
boek p. xii.) and Mattioli (Comm. Diosc. p. 561), had suggested 
a different identification. It may have been intensified because 
Clusius in 1557, in his French version of Dodoens (Hist. Pt, 
p. ult.), had figured the Tournesol as Heliotropium parvum, and 
, 
published in 1561. Here Cordus has remarked of 7d uéya 
‘ qualis sit herba et quomodo jam vocatur, ignoro cum omnibus ’; 
of To wuxpov: ‘quae sit hodie omnino ignoramus.’ This did 
not deter Gesner from identifying, in a treatise appended to that 
