E. L. EKMAN, WEST INDIAN VERNONI^, 27 



Subsect. Arborescentes. 



Frutices vel sujjrutices. Folia me^nhranacea, rarius suh- 

 coriacea, forma et puhescentia varia. Inflorescentia cymoso- 

 -scorpioidea, cymis elongatis vel in speciebus nonnullis ah- 

 hreviatis; bracteis evolutis, foliaceis. Calathidia mediocria — 

 parvula. Receptaculum planum, subnudum. Involucrum vulgo 

 late campamdatum, inierdum cylindricum ant late infundi- 

 buli forme. Pappi setce interior es persistentes aut subdeciduoe, 

 numero 20 — 50, tenues aut crassiusculce, quam exteriores dis- 

 tinctcB 5 — 15-plo longiores. Corolla 5 — 10 mm longa, glabra; 

 tubo long. V2 — ^'a corollce, extus interdum glandulis brevibus 

 nonnullis instructo; limbi laciniis apice subtus papillosis, raro 

 ipso apice pilis nonnullis munitis. Antherce 0,8 — 2,8, raro 

 3,2 mm longce, ligida long. Vo — Vs antherce, auricidis obtusis 

 aut acutis. Achcenium sericeo-pubescens . 



The subsection Arborescentes as here conceived inckides 

 species of very different habits. It matches Gleason's Scor- 

 pioidece foliatce, his smaller groups Fruticosce and Schiedearice 

 excluded. Some of his ScorpioidecB aggregatce also belong 

 here, like all his Scorpioidece reductce. It may be, however, 

 that the subsection, as here defined, is not quite monophyl- 

 etic. One of the species referred to it, namely V. Trinitatis 

 Ekman, differs somewhat in habit from the genuine Arbo- 

 rescentes, and is strongly allied to some Mexican and South 

 American species. I have tried to distinguish it by floral 

 characters from the Arbor esceyites, but in vain. Probably 

 it is, like some of its allies, an annual plant, differing as to 

 that respect from the Arborescentes; but I have no evidence 

 for this supposition. 



In fact, as easy as it is to distinguish the Arborescentes from 

 other West Indian subsections, as difficult is it to determine 

 where the line between the subsection and some South Ame- 

 rican species is to be drawn. As far south as the Argen- 

 tine province of Corrientes, species occur strongly recalling 

 the Arborescentes in habit. I am firmly convinced that numbers 

 of species from South America are to be referred in future 

 to this subsection. 



With this I have stated that the Arborescentes have their 

 nearest allies in South America, and probably the subsection 



