Ruehssia altissima (Jacq.) F.Esp.Santo & Rapini

Espírito Santo, F., Rapini, A., Ribeiro, P.L. et al. (2019). Phylogeny of the tribe Marsdenieae (Apocynaceae), reinstatement of Ruehssia and the taxonomic treatment of the genus in Brazil. Kew Bulletin 74: 30. https://doi.org/10.1007/s12225-019-9807-4

Type

Colombia, Cartagena, Jacquin s.n. (not found). [Neotype: Jacquin (1763: 84; tab. 57, selected here)].

Morphology General Habit

Lianas; stems tomentose to villous, basal stems corky and glabrous

Morphology Leaves

Leaves with petiole 1.5 – 8.2 cm long, villous; lamina 4 – 16.1 × 2.9 – 15.6 cm, cordiform, occasionally orbicular, base cordate, apex obtuse to acuminate, margins flat to slightly revolute, adaxially with 6 – 10 colleters at the base of the main vein, membranous, pilose to villous

Morphology Reproductive morphology Inflorescences

Inflorescences umbelliform or glomerulate, 10 – 30 flowers; peduncle 0.3 – 1.5 cm long, villous; bracts 4.2 – 11.5 × 1 – 4.5 mm, linear or oblanceolate, margins ciliate; pedicels 2 – 8 mm long, villous

Morphology Reproductive morphology Flowers Calyx

Sepals 3 – 6.5 × 2 – 2.8 mm, ovate or oblong-elliptic, apex obtuse, margins ciliate, abaxially villous, adaxially with or without 5 alternisepalous colleters at the base of calyx

Morphology Reproductive morphology Flowers Corolla

Corolla urceolate to campanulate, abaxially greenish, pubescent, adaxially vinaceous, 5-barbate; tube 3.7 – 5.6 × 3.8 – 4.5 mm; lobes 2.7 – 3.7 × 2.1 – 3.1 mm, broadly ovate, suborbicular or broadly oblong, recurved, apex rounded, margins not ciliate

Morphology Reproductive morphology Flowers Corona

Corona lobes 1.8 – 2.2 × 1.05 – 1.4 mm, ovate to oblong-ovate, completely fused to the anther, except for a small free apical triangular ligule (c. 0.3 mm long)

Morphology Reproductive morphology Flowers Gynostegium

Gynostegium c. 3.2 mm high, subsessile, inserted in the corolla tube; style-head c. 0.51 × 0.54 mm, conical; anthers c. 0.7 × 0.2 mm, apical membranous appendix 1.15 – 1.41 × 0.92 – 1.05 mm, triangular; corpusculum 0.13 – 0.15 × 0.04 – 0.05 mm, ellipsoid to ovoid, apex obtuse, straight; caudicles 0.4 – 0.47 mm long, distally plicate; pollinia 0.8 – 0.88 × 0.3 – 0.35 mm, ellipsoid to obovoid

Morphology Reproductive morphology Fruits

Follicles 18.2 – 20.8 × 3.5 – 7.8 cm, ellipsoid to oblong-ellipsoid, villous.

Distribution

Broadly distributed in South America, from Colombia to northern Argentina (Fontella-Pereira et al. 2004); in Brazil, the species is mainly represented in Northeast and Centre-West regions, less frequent in North and Southeast and absent in South region.

Ecology

From forests to savannas, including disturbed vegetation, also in rocky outcrops, both granitic and limestone.

Conservation

Due to the broad distribution and high number of collections, Ruehssia altissima is assessed as Least Concern: LC.

Phenology

Collected with flowers from September to June and with fruits throughout the year.

Note

Ruehssia altissima is characterised by the tomentose to villous branches, with leaves usually cordiform, pilose to villous on both sides, multiflorous and congested inflorescences, flowers with corolla abaxially greenish and pubescent, adaxially vinaceous and 5-barbate, pollinaria with a tiny corpusculum and distally plicate caudicles and large, ellipsoid to oblong-ellipsoid, villous fruits. Due to its broad distribution in South America and morphological variation, R. altissima presents several heterotypic synonyms. The synonyms presented here follow Dugand (1966) and Morillo (1978). Jacquin’s types are scattered throughout Europe (D’Arcy 1970), and that of Asclepias altissima was not found. Since there is no illustration and no evidence of a specimen of A. altissima in its protologue, we select the illustration in Jacquin (1763, tab. 57), which is sufficient for its recognition, as the neotype.

Use Materials

Used as material.

Use Medicines

Medical uses.