Grossera, Pax, 1903

Barberá, Patricia, Riina, Ricarda & Velayos, Mauricio, 2015, A new species of Grossera (Euphorbiaceae) from Equatorial Guinea, Phytotaxa 221 (2), pp. 175-180 : 179

Key to the species of sect. Grossera (extracted and modified from the key to the genus by Barberá et al. 2014)

1. Leaves 0.5–2 cm wide; petiole 0.3–0.8 cm long ............................................................................................. Grossera angustifolia

- Leaves 2.8–17 cm wide; petiole more than 0.9 cm long .................................................................................................................. 2

2. Leaves with 19–26 pairs of lateral nerves; petiole 4.3–18.5 cm long; stamens 23–30 ......................................... Grossera elongata

- Leaves with (8–)13–16(–21) pairs of lateral nerves; petiole (0.9–)1.3–6.5(–15) cm long; stamens (12–)16–18(–22) ................... 3

3. Male pedicel (4.5–)5–6(–9) mm long; male petals (2.6–)4.1–5.4(–6.3) mm long; female pedicel 22–25 mm long, glabrous; fruiting pedicel 18–20 mm long ............................................................................................................................................ Grossera major

- Male pedicel (0.8–)1.4–2.7(–3.8) mm long; male petals (1.6–)1.8–2.7(–3.5) mm long; female pedicel (2–)3.2–4.2(–9.5) mm long, densely pubescent; fruiting pedicel (4–)6.2–9.9(–14.6) mm long .................................................................................................... 4

4. Androphore densely pubescent, with multi-cellular hairs 0.5–0.7(–0.9) mm long; female calyx lobes 2.2–2.5 mm long ................ ........................................................................................................................................................................... Grossera multinervis

- Androphore glabrous, sometimes with simple, scattered hairs 0.1–0.2 mm long; female calyx lobes (1–) 1.1–1.6 mm long ............ ............................................................................................................................................................................ Grossera paniculata