Calanthe

Kurzweil, Hubert, 2010, A precursory study of the Calanthe group (Orchidaceae) in Thailand, Adansonia (3) 32 (1), pp. 57-107 : 90-92

21. Calanthe indet. ( Fig. 8 )

MATERIAL EXAMINED. — Kanchanaburi, “near the Burmese border”, XII.1983, Sukhakul sub Seidenfaden & Smitinand 9580 (C spirit [a single flower and part of an inflorescence axis]) .

DESCRIPTION

Rachis densely hairy. Floral bracts persistent, ovatelanceolate, acuminate, 18 × 7 mm, shorter than the

pedicel plus the ovary,pubescent.Flowers 41× 37 mm across, opening widely. Ovary indistinguishable from the pedicel, 23 mm long, pubescent. Sepals elliptic, mucronate, pubescent; median sepal 20 × 6.5 mm; lateral sepals 21 × 7.4 mm. Petals elliptic, mucronate, 18 × 8 mm, subglabrous. Lip unlobed, broader than long, fan-shaped and apically emarginate, 20 × 20 mm, base extensively united with the gynoste- mium, spurred, margins crisped, obtuse-dentate and undulate, with a minute tooth in the apical incision; callus in the form of three longitudinal ridges in the lower half; spur cylindric, forwards curved, 18 mm long, pubescent.Gynostemium 9 mm long, glabrous except for a few hairs at the back of the anther cap. This plant was found growing together with Calanthe vestita . According to a short description provided by Mr Sukhakul (found in the Seidenfaden working files), the pseudobulbs of the plant resemble those of C. vestita and are not constricted. The rachis is about 32 cm long and is covered with thin white hairs.Flowers were said to be white with orange-yellow at lip base. Flowering plants were found in December.

REMARKS

In a fax to Mr P. Sukhakul dated 5.II.1993 (?, date not clearly written) Seidenfaden regarded the plant as the representative of a new species which differs from C. vestita by having an unlobed lip, but also a similarity with C. labrosa was pointed out. In a later paper Seidenfaden provisionally referred this plant to C. labrosa although it was pointed out that it differs in a number of characters from typical specimens and may deserve recognition as a separate variety ( Seidenfaden 1995: 15).

The fusion lip-gynostemium is extensive which raises doubts regarding its affinity to C. labrosa . As it does not match any currently known species it is here considered as new but a formal description of the plant will have to wait until the plant is re-collected and more complete material is available for study.

Figures

FIG. 8. — Calanthe indet.,lip and gynostemium seen from the side and from above.From Sukhakul sub Seidenfaden & Smitinand 9580. Drawn by Mrs Lay Keng Ong after a pencil sketch held in the Seidenfaden working files (Copenhagen). Scale bar: 1 cm.