Sapium sceleratum

Cordeiro, Wesley Patrício Freire De Sá, Melo, André Laurênio De, Athiê-Souza, Sarah Maria, Esser, Hans-Joachim & Sales, Margareth Ferreira De, 2018, Reinstatement of Sapium sceleratum (Euphorbiaceae), an endemic species from Northeast Brazil, and new circumscription of Sapium argutum, Phytotaxa 348 (1), pp. 23-31 : 30

Key to S. sceleratum and 4 other species of Sapium occurring in Northeastern Brazil

1. Inflorescences usually clustered (2–4), terminal or axillary; leaves discolorous, above dark green, shiny, below greenish yellow, dull ................................................................................................................................................................................... S. pallidum

1’. Inflorescences always solitary and terminal; leaves concolorous (the same color above and below) ............................................. 2

2. Venation pinnate, having secondary veins without marginal arches (eucamptodromous); pistillate sepals connate ....................... 3

2’. Venation pinnate, having secondary veins with marginal arches (brochidodromous); pistillate sepals free ................................... 4

3. Shrubs up to 3 m high; leaf blade coriaceous, light-green, secondary veins conspicuous and anastomosing ............... S. obovatum

3’. Trees ca. 12 m high; leaf blade chartaceous, dark-green, secondary veins inconspicuous, separate and free .......... S. glandulosum

4. Petiole without swollen base, petiolar glands conical, 0.5–0.9 × 0.3–0.8 mm; leaf blade elliptic to obovate with cuneate to decurrent base; (6 ‒)9 ‒ 13 secondary veins; (3–)4–7 teeth per centimeter in the median portion, teeth curved towards the leaf apex; female calyx covering less than half the length of the ovary ........................................................................................................ S. argutum

4’. Petiole with swollen base, petiolar glands cylindrical, 0.8–1.5 × 0.6–0.8 mm; leaf blade lanceolate, sometimes elliptic, with rounded to obtuse base; 15–18 secondary veins; 6–11 teeth per centimeter in the median portion, teeth straight pointing outwards; female calyx covering more than half the length of the ovary ..................................................................................... S. sceleratum