Herb, up to 1.2 m high, branched. Stems and branches up to 1.1 cm in diam., quadrangular, winged, wings 1-1.3 mm wide; internodes 2.5-13.5 cm long. Leaves sessile, cauline, evenly positioned; blade subcoriaceous to membranaceous, oblanceolate (specimen from Venezuela elliptic), 4.3-20.7 x 2.9-6.2 cm, margin not thickened, flat, apex acute to obtuse, base attenuate or obtuse just below inflorescence. Inflorescence 16-40-flowered; bracts ovate, 2.2-3.8(-8.1) mm long, apex acuminate to cuspidate; pedicel 6-9 mm long. Flowers erect to horizontal; calyx green, 6-8 x 5-7 mm; lobes ovate, 3-4 x 3-4 mm, upward facing hook protruding from apex of glandular area, hook 1.3-2.1 long, margin membranaceous, apex obtuse; corolla green, with dark green spot on apex of each corolla lobe, funnel-shaped to tubular, 20-27 mm long, 10-18 mm wide at mouth, lobes ovate, ca. 6 x 7 mm, apex obtuse; stamens not exserted, filaments 10-12 mm long, corona present at insertion point, straight to curved downward close to anther, anthers white-yellow, elliptic, 1.8-3.2 mm long, straight; pollen exine with fine reticulum interspersed with thickend, knob-like muri; pistil ca. 18 mm long, ovary ca. 4.4 x 2.1 mm, style ca. 11 mm long, stigma lobes elliptic, 2.4-2.8 x ca. 1.8 mm. Fruit nodding, brown, ellipsoid, 9-17 x 4-8 mm; seeds brown, 0.1-0.6 mm in diam.
French Guiana present present, Southern America: Venezuela (Venezuela present)
Venezuela and French Guiana; 4 collections studied, of which 3 from French Guiana (FG: 3).
Herba foliis subcoriaceis vel membranaceis apice acutis vel obtusis, calyce lobis extus uncis crassis antrorsis areis glandulosis superpositis munitis, staminibus in insertione lobis alternantibus plusminusve coronam formantibus.
Specimens have been observed from the Venezuelan states of Amazonas and Bolívar, along the Río Orinoco or one of its smaller tributaries that have well defined to slight bumps on the calyx lobes vs. prominent hooks as observed in
C. hamatus. These specimens are also characterized by stems that are weakly quadrangular to terete vs. strongly quadrangular and 4-winged in C. hamatus, and staminal pockets or reduced corona vs. a corona twice as large as in C. hamatus. Considering the presence of any structure protruding from the apex of the glandular area is a character unique not only to the genus, but to the family, these specimens are considered potential intermediate taxa between C. hamatus and an unknown parental taxon. Attempts to amplify DNA from such specimens have been unsuccessful and further research is needed to determine the status of these specimens. At this point, they are not considered a part of C. hamatus. For additional details see Lepis (2009).