Spigelia subg. Spigelia sect. Graciles, Progel, 1868

Macedo, Arthur, Pessoa, Edlley & Alves, Marccus, 2019, A new species of Spigelia L. sect. Graciles (Loganiaceae) from northeastern Brazil, Phytotaxa 404 (4), pp. 146-154 : 152

Key to the species of Spigelia subg. Spigelia sect. Graciles in northeastern Brazil

1. Calyx lobes 0.7–1 mm long; corolla 5–6 mm long .................................................................... S. fontellae Fern. Casas (2005: 250)

- Calyx lobes 2–3 mm long; corolla 1.1–3.3 cm long...........................................................................................................................2

2. Corolla 3–3.3 cm long; anthers exserted ........................................................................................................................... S. pulchella

- Corolla 1.1–2 cm long; anthers inserted.............................................................................................................................................3

3. Corolla salverform; stigma exserted and often hidden among the lobes......................................................................... S. alborubra

- Corolla infundibuliform; stigma included..........................................................................................................................................4

4. Leaves venation pinnipalmate; distal portion of the corolla tube with constriction in middle region, lobes deltoid to widely deltoid............................................................................................................................................................................. S. spartioides

- Leaves venation hyphodromous; distal portion of the corolla tube with no constriction, lobes ovate, widely ovate, narrowly elliptical to elliptical ...........................................................................................................................................................................5

5. Flowers 2–8 per inflorescence; distal portion of the corolla tube 7–8 × 3–3.5 mm .................... S. elsieana Fern. Casas (2005: 246)

- Flowers 14–28 per inflorescence; distal portion of the corolla tube 3.8–4.5 × 1.7–2.8 mm ..............................................................6

6. Proximal portion of the corolla tube 1–1.2 mm wide, distal portion of the corolla tube 1.7–1.9 mm wide, lobes elliptical to narrowly elliptical ............................................................................................................................................................................... S. gracilis

- Proximal portion of the corolla tube 1.8–2.2 mm wide, distal portion of the corolla tube 2.5–2.8 mm wide, lobes ovate to widely ovate ............................................................................................................................................................................... S. linarioides