Rhamnidium, Reissek, 1861

Figueira, Maurício & Schindler, Bianca, 2021, Rhamnidium riograndense (Rhamnaceae), a new species from southern Brazil, Phytotaxa 510 (1), pp. 53-60 : 58

Key to the species of South American Rhamnidium

1. Trees or shrubs, usually higher than 2 m tall......................................................................................................................................2

- Subshrubs with xylopodium, usually up to 1 m tall ...........................................................................................................................4

2. Leaves and inflorescences glabrous; leaf blade with apex acuminate; pedicel 4.0– 4.5 mm long ..................................... R. glabrum

- Leaves and inflorescences pubescent to velutinous; leaf blade with apex acute to obtuse; pedicel 2.5–3 mm long.........................3

3. Leaf blade chartaceous; petiole 0.9–1.4 cm long ( Argentina, Brazil, Bolivia, Ecuador, Paraguay and Peru) ........... R. elaeocarpum

- Leaf blade membranous, petiole 0.2–0.5 cm long (northeast Brazil) ..................................................... R. molle Reissek (1861: 95)

4. Secondary veins 5–6(–7) pairs per leaf, tertiary veins flat and reticulate, punctiform glands regularly spread in the abaxial leaf blade surface; inflorescence lax, peduncles> 5 mm long, glabrous; hypanthium and sepals externally glabrous ( Paraguay) ........... .................................................................................................................................................................................... R. hasslerianum

- Secondary veins 7–10 pairs per leaf, tertiary veins prominent and perpendicular, punctiform glands on the leaf blade margin and scattered in the abaxial surface; inflorescence congest, peduncles <2.2 mm long, puberulous; hypanthium and sepals externally puberulous ( Brazil, state of Rio Grande do Sul,) ....................................................................................................... R. riograndense