Chromolaena (King & Robinson, 1970)

Ferlay, Benjamin, 2025, Neotypification and new combination for an endemic species of Martinique (Lesser Antilles) in the genus Chromolaena (Eupatorieae, Asteraceae), Phytotaxa 698 (1), pp. 51-57 : 55-56

Chromolaena in Martinique

Currently, five species of Chromolaena are reported for Martinique. C. trigonocarpa and C. medullosa are present in montane areas, while C. odorata (L.) R.M.King & H.Robinson (1970: 204) is a rather common scrambling shrub in xeromesophilic disturbed environments (Hahn 171 [L.3033279], Keil 16532 [OBI135926], B. Ferlay 1215 [P00942110, MTK003897], B. Ferlay 2256 [MTK006138]). However, the presence of Chromolaena corymbosa (Aubl.) R.M.King & H.Robinson (1970: 200) and Chromolaena ivifolia (L.) R.M.King & H.Robinson (1970: 202) are doubtful.

Chromolaena ivifolia was recorded in Guadeloupe (Duss 28, NY1629282). In the Flore Phanérogamique (Duss 1897), it is specified that the species is not present in Martinique. Nevertheless, Howard (1989) and Fournet (2002) mentioned it for Martinique, adding “location to be specified”. My searches for specimens in the Herbaria have enabled to discover of a single specimen from Duss (Duss 4072 [ US 00877308], image available at http://n 2t.net/ark:/65665/ 39be84beb-a15c-492d-9cd8-f70919c7d030), collected in Martinique, in the heights of Fond Layette (Bellefontaine), which is said to be rare. Since then, no further specimen was recorded, and the species might be extinct.

One putative specimen of C. corymbosa from Martinique was collected by Hahn (Hahn 397 [L.3692055], image available at https://medialib.naturalis.nl/file/id/L.3692055/format/large), and first identified as Eupatorium atriplicifolium Lamarck (1786: 407) , which is now a synonym of Chromolaena corymbosa . However, a close examination of this specimen shows that the leaf base is not distinctly truncate as in C. corymbosa , but slightly cuneate, or with a portion of the blade slightly decurrent along the upper part of the petioles. Also, the leaf apex is acute. It is clear that this specimen belongs to C. trigonocarpa . Fournet (2002) expressed doubts about its presence, when he wrote ‘Ecology and location to be specified.’ Therefore, Chromolaena corymbosa has been incorrectly reported for Martinique.