Species Information - Dendrobium parvulum

Flowers red, pink-purple, violet, blue or whitish yellow, lip apex usually orange to orange-red.

Epiphyte, growing both on tree trunks as well as smaller branches in montane forest, rarely terrestrial. Altitude 600 to 2650 m.

Sulawesi, New Guinea, Bougainville, Solomon Islands, Caroline Islands (Ponape), Fiji, Vanuatu.

Papua (Waigeo Island; Japen Island; Central Mountain range); Papua New Guinea (widespread in the mountains, but largely absent from the northern ranges).

This pretty little orchid, of which the bluish violet form is a real jewel, is not easily cultivated, and probably best grown in large shallow saucers in view of its creeping habit and intolerance of drought. It does require good drainage, coolness, and f

Throughout the year, but perhaps peeking from October to April. Flowers last 3-4 months, except in the autogamous form described as Dendrobium delicatulum subsp. huliorum, which has flowers lasting only about two weeks.

• Reeve, T.M. & P.J.B. Woods. 1990. Notes Roy. Bot. Edinburgh 46: 222, fig. 18, pl. 11B-D (as Dendrobium delicatulum auct. non Kraenzl.: T.M.Reeve & P.B.Woods).
• Lewis, B. & P.J. Cribb. 1991. Orchids of the Solomon Islands and Bougainville: 184, fig. 43 a-j (as Dendrobium delicatulum auct. non Kraenzl.).

This species was wrongly identified as Dendrobium delicatulum Kraenzl. by Reeve & Woods (1981 & 1990). At that time they had not seen any type material of that species and had assumed this to be lost. However, a type specimen is still extant at the Hamburg herbarium, where it was examined and photographed by Mark Clements. Clements found that the true D. delicatulum is in fact very similar to, and probably conspecific with Dendrobium subacaule. Clements has kindly showed us his photograph and we are convinced that he is right. Moreover, Schlechter's illustration of D. delicatulum also undoubtedly represents D. subacaule, so we have decided to relegate D. delicatulum to the synonymy of D. subacaule. As a result, the species formerly misidentified as Dendrobium delicatulum should now be known as Dendrobium parvulum.

Reeve & Woods distinguished three subspecies in what they called Dendrobium delicatulum: D. delicatulum subsp. parvulum, D. delicatulum subsp. delicatulum and D. delicatulum subsp. huliorum. Of these the first two are distinguished only by the slightly larger flowers (12-15 mm long) of subsp. parvulum compared with subsp. delicatulum (7-12 mm). Subsp. huliorum differs from the typical subspecies in the following respects: Plant often larger, up to 4.5 cm high; pseudobulbs 5-15 by 2-9 mm, greenish yellow to yellow; leaves green on both sides; flowers 7-10 mm long, not widely opening and usually self-pollinating, sometimes cleistogamous.

We consider it preferable to recognise these subspecies only at an informal level, where they may be referred to as e.g. 'large-flowered form' and 'autogamous form'.

Dendrobium parvulum is easily recognised by its mat-forming habit, 2-leaved pseudobulbs, very small, relatively broad leaves, and 5-ribbed ovary. Only Dendrobium putnamii is similar, but can be distinguished by its linear-lanceolate leaves and triangular ovary.