Tragia, Linnaeus, 1753

Martínez-Gordillo, Martha, Colín, Rafael Torres & Gernandt, David S., 2015, A new species of Tragia (Euphorbiaceae) from Oaxaca, Mexico, Phytotaxa 202 (2), pp. 161-164 : 162

Key to the species of Tragia from Oaxaca

1. Ovary and fruit densely covered with glandular and branching trichomes..................................... T. pacifica McVaugh (1961: 203)

- Ovary and fruit without glandular and branching trichomes..............................................................................................................2

2. Inflorescence with stipitate or sessile glands......................................................................................................................................3

- Inflorescence mainly nonglandular....................................................................................................................................................4

3. Leaves with entire margin; inflorescence with dense stipitate glands........................... T. mexicana Müller Argoviensis (1865: 181)

- Leaves with serrate or crenate margin; inflorescence mainly with sessile glands .......... T. glanduligera Pax & Hoffmann (1919: 55–56)

4. Climbing vines, to 2.5 m tall. .......................................................................................................... T. volubilis Linnaeus (1753: 980)

- Plants erect, trailing, twining, not exceeding 60 cm ...........................................................................................................................5

5. Leaves triangular to triangular-lanceolate, petiole length 0.1–2.5 cm; inflorescence length 0.7–2.4 cm; peduncle equal to or shorter than axis, up to 4 mm long in fruit; styles united for ½–⅓ of their length ...................................................... T. nepetifolia

- Leaves ovate to ovate-lanceolate, petiole length 2.9–5.8 cm; inflorescence length 2.5–9 cm, peduncle longer than axis, 1.5–6.5 cm long; styles united for ¾ of their length................................................................................................................... T. chiltepeca