Monographs Details: Decagonocarpus cornutus var. congestus Cowan
Authority: Maguire, Bassett & Wurdack, John J. 1958. The botany of the Guayana Highland--Part III. Mem. New York Bot. Gard. 10: 1-156.
Family:Rutaceae
Description:Latin Diagnosis - A var. cornuto foliis ramulorum ad apicem congestis, minoribus (ea. 25 X 12 mm), petiolis brevioribus (ca. 3 mm), ealyce leviter puberulo lobis ciliolatis, corollarum tubo breviore (ca. 23 mm longo) plerumque plus minusve puberulo differt.

Discussion:

Type Collection: Maguire 31693 (holotype NY), "shrub to 1 m. lvs. succulent, fls. orange-red. Occasional on summit of Cerro Guanay, 1800 m, Terr. Amazonas, Venezuela, Feb 2, 1951." Paratype: same data and collector, 31713.

This species differs from D. oppositifolius, the only previously known species in the genus, in size and shape of the leaves and of the calyx and in the posture of the corolla-lobes. It differs also in having strikingly horned fruits which have only a single ridge on the back, rather than two as in D. oppositifolius (fruits of var. congestus have not been seen but they are very likely similar to those of the typical variety). The specific epithet is intended to call attention to the horned fruits.

Var. congestus has the leaves somewhat smaller and congested at the branchlet tips; these plants also have shorter petioles, a pubescent calyx, and usually a puberulous corolla.