Key based on leaf anatomy (transverse section) to the graminoid species of Dendrobium in New Caledonia

1. Leaves thick, vascular bundles in two parallel lines, very numerous (> 32), largest with diameter <½ the thickness of the leaf blade ......................................................................... D. crassifolium Schltr.

– Leaves thin, vascular bundles in one line, less numerous (<30), largest with diameter> ¾ the thickness of the leaf blade ................................................................................................................. 2

2. Vascular bundles <15, midrib prominent or not, largest bundles in position 2 or 3(–4–5) .............. 3

– Vascular bundles> 22, midrib prominent, largest bundle in position 5(–6) ..................................... 4

3. Supernumerary fibre bundles numerous on both sides (> 35), large (Fig. 4A), largest vascular bundle in position 2, midrib prominent in leaf section ............................................. D. unicarinatum Kores

– Supernumerary fibre bundles only on abaxial side, few (<15), small, largest vascular bundle in position 3(–4–5), midrib not prominent in leaf section ....................................................................... ......................................................................................... D. butinii M.Pignal & Munzinger sp. nov.

4. Margins obtuse in transverse section (Fig. 4 Ba) ................................................................................. .............................................................................. D. letocartiorum Munzinger & M.Pignal sp. nov.

– Margins truncate in transverse section (Fig. 4 Bb) .................................... D. camaridiorum Rchb. f.