46 ARKIV FOR BOTANIK. BAND 13. N:0 15. 



ganz gerecht ist; denn Swartz hat doch erkannt, dass die 

 Conyza arborescens eine Vernonia ist, und hat die Combina- 

 tion richtig vollzogen. Was bei ihm darauf folgt: Beschrei- 

 bung und Vaterland ist allerdings falsch. Wenn Sie genau 

 sein wollen, konnen Sie schreiben: 



V. arborescens (L.) Sw. (quoad syn. Linn., non quoad 

 descript. nee patriam. 



Auch die Nordamerikaner verfahren so von ihrem Princip 

 der 'Priority in place' aus. 



For further illustration to this point I refer to Hitch- 

 cock, North American species of Panicum, Contr. U. S. Nat.. 

 Herb., Vol. 15, 1910, p. 6, and to Urban, Symb. Antill., Vol. 

 VII, 1913, p. 342. 



V. arborescens (L. ) Sw. is evidently the Vernonia of the 

 Windward Islands, being known from Martinique, Santa 

 Lucia, St. Vincent, Bequia and Margarita. There are only 

 two points indicating a wider distribution of the species. 

 In the Prodromus Herbarium I found a plant from Havana 

 collected by de la Ossa, and referred to V. arborescens 

 (L.) Sw. (3 ovatifolia DC; it is, however, a typical V. arbo- 

 rescens (L. ) Sw. Nothing is known about de la Ossa collecting 

 in Martinique, so that it must be supposed that the ' plant 

 occurred at Havana. Most probably it grew in the bo- 

 tanical gardens of that town, of wich de la Ossa was 

 director. Further, Gleason asserts that he has seen specimens 

 of his V. ventosa from Guadeloupe. I venture to suppose that 

 this statement is due to a confusion with the large-headed 

 form of V. albicaulis Pers. common in that island. In 

 fact, Duss n. 2812, representing this very form, was deter- 

 mined by Gleason in a letter to Prof. Urban as V. ventosa 

 Gleason. In his Studies he cites the same plant as V. ico- 

 santha DC. (Gleason, 1913, p. 307). 



An interesting locality for the species is the island of 

 Margarita near the coast of Venezuela, rather distant from 

 its main region. It occurs there in a somewhat different 

 form, hardly at first sight recognizable as V. arborescens. 

 In habit it resembles a rigid V. Trinitatis Ekman, but is easily 

 distinguished from that species by its small heads. 



Like many West Indian Vernonia?, V. arborescens is ex- 

 tremely variable. I need not insist that I have repeatedly 

 looked over the abundant material on the chance of discov- 



