Key to the graminoid species of Dendrobium in New Caledonia

Grass-like stems. Inflorescences 1- or 2-flowered, exactly opposite the leaf blade.

1. Flowers non-resupinate. Inflorescences 1-flowered, lamina without any visible depression. Fruit sub-globose ( Dendrobium sect. Biloba) ............................................................................................ 2

– Flowers resupinate. Inflorescences always biflorous, lamina with a visible depression, sometimes ‘V’-shaped (Fig. 1R), in the lower third; fruit fusiform ( Dendrobium sect. Grastidium)................. 3

2. Stems bifaciate. Sepals 12 × 2–4 mm, lateral sepals triangular. Petals linear or slightly lanceolate, 11 × ca 1 mm. Lip red, carina, 3.......................... D. letocartiorum Munzinger & M.Pignal sp. nov.

– Stems cylindrical or slightly flattened. Sepals 4–4.5 × 2.4–3 mm, lateral sepals triangular-ovate. Petals ovate, asymmetrical, ca 4 × 2 mm, lip white, carina, 1....................... D. unicarinatum Kores

3. Leafy stem thick, slightly fleshy, weakly flattened; lamina of leaf wide and short, 50–70 × 9–15 mm, ovate, coriaceous, fleshy................................................................................. D. crassifolium Schltr.

– Leafy stem thin, terete, not fleshy; lamina of leaf narrow, 35–100 × 1.5–4 mm, slender, chartaceous and not crassulescent ......................................................................................................................... 4

4. Leaf blade 45–100 × 4–5 mm; sepals and petals at least 30 mm long; adventive plantlets frequent; sepals attenuate ........................................................................................... D. camaridiorum Rchb. f.

– Leaf blade ca 35–40 × 1.5–2 mm; sepals and petals <10 mm long; adventive roots present, but plantlets absent; sepals triangular, abruptly narrowed forming an acumen ca 4 mm long ................. ......................................................................................... D. butinii M.Pignal & Munzinger sp. nov.