44 ARKIV FÖR BOTANIK. BAND 13. N:0 15. 



the specimen in the Surian Herbarium *(P) as the type of 

 Conyza arborescens L. rather than the plant in Linn^fs's her- 

 barium, as this only partly corresponds with his description. 

 LiNN^us himself seems to have laid more stress upon the plant 

 figured by Pltjmier, to judge by his specific name of the 

 plant, G. arborescens, the name taken from »Eupatorium arbo- 

 resceyis floribus cceruleis», Plum. 1. c. It is puzzling that 

 he has not quoted the sjmonym in Browne, Jam., p. 313, 

 under his C. arborescens, which he would certainly have 

 done, if he had considered the Jamaican specimen in writing 

 the description. It seems as though G. arborescens had been 

 originally based upon the figure of Pltjmier, and had had its 

 description afterwards somewhat modified according to the 

 Jamaican plant. 



If the name G. arborescens goes with the description, 

 it must be the Jamaican plant which should be named V. ar- 

 borescens (L.) Sw. The Martinique plant of Plumier should 

 then be called F. icosaniha DC. 



Later on in the j^ear 1759 Linn^us attributed, in Pu- 

 gillus Jamaicensium plantarum, Amoen. Acad. Vol. 5, p. 

 406, to his C. arborescens the synonym of Browne already 

 mentioned, and another synonym also referring to the Jam- 

 aican species from Sloane. In this way the incorrect 

 application of G. arborescens to the Jamaican plant became 

 more decisive. 



Olof Swartz, in fact, on his return from Jamaica, saw 

 in London the plant of Browne and Sloane, and taking 

 this to be the genuine Conyza arborescens, he described it in 

 his Observationes, p. 304. On the same plant he afterwards, 

 in Flora Indies occidentalis, based his Vernonia arborescens. 

 Thus the Vernonia arborescens became definitely a Jamaican 

 plant. Consequently, when it became evident that the Mar- 

 tinique plant was different from the Jamaican one, the former 

 was described as a new species, viz. V. icosaniha DC. A general 

 vagueness, however, as to the correct application of the name 

 F. arborescens gradually crept in, so that nearly all species 

 of the Arborescentes have borne the name. 



Thus do matters stand up to the end of the nineteenth 

 century. At length, the demand for a consistent nomen- 

 clature had begun to make itself felt. The routes of the 

 ancient travellers were studied in order to ascertain where 



