AFRICAN

ORCHIDS

Liparis caulescens Frapp. ex Cordem., Fl. Réunion: 186 (1895).
Description:
Medium to large erect terrestrial or lithophytic plant, 14 – 33 cm high, rhizome short, ascending, roots wiry, more or less pilose, c. 1 mm diam. Pseudobulbs slender, stem-like, a little inflated at the base, up to 25 cm × 6 – 15 mm, partly covered by 4 – 5 thin amplexicaul sheaths, partly overlapping, up to 5 cm long, with 2 – 3 (rarely 4) apical sub-petiolate leaves. Leaves spreading, asymmetric, lanceolate to elliptical-lanceolate, acuminate, undulate, the veins obliquely convergent, more or less glossy, contracted into a 10 – 25 mm petiole at the base, overall 8 – 10 × 4 – 5.5 cm, the third leaf usually smaller, dark green. Inflorescence erect, a little longer than the leaves, carrying up to 15 flowers but usually fewer, up to 11 cm. Peduncle with a few linear-lanceolate peduncle sheaths becoming sterile bracts, 7 – 10 mm long. Rachis loosely racemose in the upper half of the inflorescence, up to 7 cm long. Floral bracts spreading, linear-lanceolate, acuminate, the lower ones considerably longer than apical ones, up to 13 × 3 mm, green. Flowers medium in size, up to 15 × 10 mm, ovary green, sepals and petals yellowish-brown, lip dark brown to ochre, darker towards the middle becoming a dark orange-red on the disk and base of column, column white becoming brown towards the base; the whole flower turning more orange with age. Pedicel and ovary glabrous, costate, 12 – 14 × 0.8 – 1.1 mm. Dorsal sepal reclining, ligulate-lanceolate, 8 – 12.5 × 1.5 – 2.1 mm. Lateral sepals curved beneath the lip, ovate to lanceolate, 7.5 – 9.9 × 3.6 – 4.5 mm. Petals margins incurved, spreading and curved upwards, obliquely linear 9 – 10.5 × 1.2 – 1.6 mm. Lip strongly curved towards the base, broadly obovate, with very small auricles at the base, rounded to emarginate at the anterior margin, the margins undulate, with a distinct two-horned callus at the base, 7.1 – 8.9 × 6.3 – 8.6 mm. Column relatively short, 3 – 4.5 × 1 – 1.5 mm, curved at the apex, with small triangular wings towards the apex. Anther oblate, rounded at the front, c. 0.8 × 0.6 mm. Pollinia in 2 pairs, ovoid, c. 0.5 × 0.3 mm.
Etymology:
Refers to the stem-like pseudobulbs.
Habitat:
Terrestrial or lithophyte in forest, common on rocky cliffs of shady ravines. Usually in dark and wet places in the rainforest at medium elevation. Altitude: 800 – 1500 m.
Flowering time:
February to May.
Recognition:
A medium-sized to large plant with a long slender pseudobulb, two to three sub-petiolate asymmetric leaves, a loosely racemose rachis and medium-sized flowers, with a brown, broadly ovate lip with a two-horned callus at base and a rounded anther.
The species shares a similar habit, including the somewhat asymmetric leaves, its brownish-yellow flower colour and lip shape with Liparis rivalis from Madagascar but plants of L. caulescens are a little shorter, the spike habit is laxly racemose (vs densely racemose), fewer and with larger flowers, the lip with a more distinct callus, a larger, differently shaped column with angular vs rounded wings (Table 6). They may well have evolved from a common ancestor. It is somewhat similar in habit to Liparis gracilipes and L. danguyana from Madagascar but the leaves are considerably longer and asymmetric lanceolate vs elliptic-oval, while its flowers are at least 1/3 larger and the lip broadly obovate vs suborbicular.
Notes:
The history of the species is complex, it appears to have been known by various botanists working at the end of the 19th century and consequently several different names have been found in herbaria. The earliest herbarium sheets referring to this species are from Achille Richard’s herbarium: two sheets in Paris (Richard 402) labelled as ‘Malaxis flavescens’, dated 1837 from Bourbon [Réunion] and one sheet in the Kew Lindley herbarium labelled as ‘L. vaginata A.R. m. sp. Sp. nova. Ile Bourbon Richard’. Most of the early collections (e.g. Lavallée 269, Armange s.n. in P) were misidentified as M. flavescens, now Liparis flavescens, which was described and illustrated by Du Petit-Thouars (Thouars 1822: t.25) and was one of the few Liparis then known and similar, at first sight, to L. caulescens. Further Richard herbarium material found its way to the Reichenbach herbarium in W (643) where it is annotated ‘Liparis vaginata nob. sp. nov.’. From the above it seems that Richard intended to describe the species as Liparis vaginata but never did so. The Richard specimen at K-Lindl. was traced on paper by Reichenbach f. (now in W) and the tracing is annotated ‘Liparis vaginata A. Rich. sp. nov’ but additionally as ‘Lip. caulescens Boiv. Isle Bourbon’ and also labelled as ‘L. longa Rchb.f cf. Linnaea”. Liparis longa was described by Reichenbach in Linnaea (1877: 98) at the end of a lengthy series of novelties, most with a reference to type material except for L. longa which was the last in the series. The description is fairly detailed and mentioned a plant with a long stem, sub-opposite leaves and a lip with two teeth at the base of the lip. It is likely that Reichenbach was referring to the Richard material and decided to apply his own epithet and not the one suggested by Richard. Liparis longa is an earlier name for the species but under the rules of nomenclature (ICN article 7.9) Reichenbach’s name cannot be accepted as it lacks any type material. In 1887, Ridley included L. longa in his monograph but added no further information.
Distribution:
Réunion
References:
Flore de l'ile de la Reunion1895; Malaxideae (Orchidaceae) in Madagascar, the Mascarenes, Seychelles and Comoro Islands Kew Bulletin volume 75, Article number: 1 (2020)
Images:
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