Reduction of the Genus Heynea Roxb. ex Sims to Trichilia P.Br. (Meliaceae)

The identification of some Indo-Chinese simaroubaceous plants reduced by Mr H. P. Nooteboom to Heynea led to a closer examination of the genus Heynea, its taxonomical status, the species names assigned to it, and its synonymy. Up to the present day Heynea has almost unanimously been distinguished as a separate genus in the alliance of Walsura and Trichilia. Baillon (1875) united Heynea with Walsura under the oldest generic name Heynea. In the same year Kurz (1875) also united them under the generic name Walsura and he was followed by Harms (1897) who erroneously argued that Walsura should have precedence over Heynea. In the second edition of the Natiirliche Pflanzenfamihen (1940) he again separated them keeping Trichilia, Heynea, and Walsura together as the sub tribe Trichiliinae, including also the more distant Ekebergia and Owenia (l.c. 39). Heynea is closest to Trichilia, both genera differing from Walsura in the dehiscing, capsular fruit. The differences Harms gave for discriminating Trichilia and Heynea cannot be applied through overlapping of their characters and the main distinction that remains is geographical: Trichilia being a large, polymorphous genus developed in America, Africa, and also recorded from Madagascar and Mauritius, Heynea having only two species and known only from tropical Indo-Malaysia. In the past various other Malaysian or Polynesian species have been referred to Trichilia, but have appeared to belong to various other genera, mostly Dysoxylum; see under excluded species.