Tetranema, Sweet, 1830

Christenhusz, Maarten J. M., 2010, Nomenclatural corrections in Mesoamerican Plantaginaceae and a new species of Tetranema from Honduras, Phytotaxa 14 (1), pp. 56-60 : 57

Key to the species of Tetranema

1. Stamens included; corolla funnel-shaped, white with violet steaks to purple or blue ..................................................... 2

1. Stamens exserted from the throat of the corolla (but not exceeding the upper corolla lobe); corolla tubular, red or scarlet................................................................................................................................................................................... 3

2. Leaves condensed in a pseudo-rosette, obovate, the internodes short (≤ 1 cm) ................................................ T. roseum

2. Leaves spaced along the stem, oblanceolate, the internodes longer (≥ 3 cm) ...................................... T. michaelfayanum

3. Plant 25–50 cm; corolla lobes 2–4 mm, <1/5 the total corolla length; floral bracts ca. 6–10 mm .......... T. megaphyllum

3. Plants (35–) 80–200 cm; corolla lobes 11–13 mm long,> 1/5 the total corolla length; floral bracts 0.5–5 mm .............. 4

4. Corolla 2.6–3.5 cm, pubescent within in a band of flat, yellow hairs along the entire ventral surface and onto the lower lobe; inflorescence many-flowered (14–30 flowers), the peduncle purple; leaf apex rounded to short-acuminate ....... ................................................................................................................................................................ T. floribundum

4. Corolla ca. 4.9–5.5 cm, glabrous throughout or (rarely) pubescent on lower lobe and at mouth; inflorescence few-flowered (2–12 flowers), the peduncle green; leaf apex long-acuminate ...................................................... T. gamboanum