Habitat and distribution. Tanaecium crucigerum occurs in wet forests in the Lesser Antilles (Dominica, Martinique), Trinidad and Tobago, Costa Rica (Limón), and Venezuela (Anzoátegui, Apure, Cojedes, Delta Amacuro, Guárico, Portuguesa). Phenology. Flowering: April to July, and October; fruiting: February, April to July, and October to November.
 Notes. Like Lohmann and Taylor (2014), we were also unable to locate the lectotype of T. crucigerum selected by Howard (1989: 334), the collection J. Imray 95 supposedly deposited at K. This collection is thus presumed lost. As such, we select another Imray collection from Dominica studied by Seemmann (1856) deposited at K as lectotype. We selected the material J. Imray 94 as lectotype due to high quality of this material.
 This species is morphologically most similar to T. jaroba, sharing many characters such as the simple tendrils, wide infundibular corollas, and wingless seeds (Tab. 1). Tanaecium crucigerum differs from T. jaroba by the whitish-tomentose leaflets on the abaxial surface (vs. glabrous or pubescent leaflets on the abaxial surface in T. jaroba).