Dendrobium crassifolium Schltr., 1906

Pignal, Marc & Munzinger, Jérôme, 2020, Morphological and anatomical investigation of New Caledonian graminoid Dendrobium (Orchidaceae) with the description of two new species, European Journal of Taxonomy 633, pp. 1-26 : 11-13

Dendrobium crassifolium Schltr.

Figs 1 K–L, O, 5 E–F, 7

Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie Heft 1, 39: 75 ( Schlechter 1906). – Type: NEW CALEDONIA – Province Nord • près “ Ou-Hinna ” [ Oua Hinna ]; alt. 900 m; 2 Jan.1903; Schlechter 15603; holotype: B (destroyed); lectotype: P[ P00121168 ]!, here designated; isolectotype: K[ K001085479 ] photo seen, BM[ BM000505888 ] photo seen ).

Etymology

The epithet refers to the texture of the leaf.

Material examined

NEW CALEDONIA – Province Nord • Haute vallée de la Tchamba ; [21°1′56″ S, 165°13′36″ E]; alt. 100–200 m; gallery forest near the river; 28 Dec. 1965; fl.; H.S. MacKee 13751; P [ P00124990 ] • Haute Tchamba; [21°3′23″ S, 165°15′22″ E]; alt. 50 m; gallery forest; 13 Nov. 1969; fl.; H.S. MacKee 21172; P[ P00124992 ], P[ P00124993 ], P[ P00124994 ] • Plateau of the Dôme Tiébaghi ; [20°27′37″ S, 164°12′7″ E]; alt. 500 m; 20 Jun. 1972; fl.; H.S. MacKee 21337; P[ P00124991 ] • Touho, Ponandou ; [20°49′12″ S, 165°13′45″ E]; alt. 10–100 m; forest on serpentine substrate; 2 Jan. 1973; H.S. MacKee 26141; P [ P00124995 ] • Poindimié: Povila ; [20°57′0″ S, 165°17′16″ E]; alt. 400–500 m; humid forest, schistose crest; 21 Mar. 1975; H.S. MacKee 29892; P [ P00124996 ] • Touho: Ponandou ; [20°49′11″ S, 165°14′14″ E]; alt. 30 m; gallery forest, schists; 22 Mar. 1975; H.S. MacKee 29897; P [ P00124997 ] • Poindimié ; [20°56′27″ S, 165°19′39″ E]; alt. 30 m; humid forest, schists; 14 Jun. 1976; fl., cult.; H.S. MacKee 31399 (leg. Aymard); P [ P00124998 ] • Haute Amoa: base du Mont Grandié ; [20°58′59″ S, 165°9′15″ E] alt. 50 m; gallery forest, serpentine substrate; 25 Dec. 1976; fl.; H.S. MacKee 32136; P [ P00124999 ] • Poindimié: Ndiambi ; [20°57′57″ S, 165°19′14″ E]; alt. 200 m; 23 Nov. 1987; H.S. MacKee 43781 (leg. Aymard); P [ P00123284 ], P [ P00354112 alc.] • Flowered in greenhouse in Nov. 1983; P. Morat 5321 (original data: Bopope, Feb. 1977, collected by P. Morat); P [ P00121169 ] • On the mountains at Ou-Hinna ; [20°30′22″ S, 164°42′55″ E]; alt. 900 m; 2 Jan. 1903; fl.; R. Schlechter 15603; P [ P00121168 ] . – Province Sud • Haute Yaté, Rivière Bleue ; [22°6′46″ S, 166°41′4″ E]; alt. 200 m; humid forest, serpentine substrate; 1 Feb. 1985; H.S. MacKee 42443 (leg. Bégaud); P [ P00125000 ] • On the mountains at Ngoye ; [21°49′8″ S, 166°28′23″ E]; alt. 300 m; 13 Nov. 1902; fl.; R. Schlechter 15277; LY[LY0562048 ].

Description

Erect or downward arching epiphyte. Roots whitish, ca 1–2 mm wide, at the base of the plant (axillary roots lacking). Stems 20–100 cm long, robust. Sheaths of the oldest leaves not always covering the stem. Leaves dark green shiny above, lighter below, thick and coriaceous. Lamina shortly ovate to elliptic, 50–70 × 9–15 mm. Midrib visible, secondaries weakly visible. Lamina with a visible V-shaped depression printed around the lower third of the stem. Base abruptly narrowed, apex attenuate, emarginate, with two sub-equal lobes. Sheath striated in its entire length, with edge oblique, opposite to the lamina and applied to the stem. Inflorescence 2-flowered. Ovary resupinate. Flower yellow. Sepals triangular, 10 × 2.9 mm. Petals elliptical, 10 × 2.5 mm. Lip trilobed ca 6 × 5 mm. Lateral lobes with papillose hairs, median lobe with distinctive carina, extending into short papillate hairs. Edge slightly fimbriate. Mentum ca 3 mm. Column about 1.7 mm long. Fruit fusiform ca 8 × 10 mm long and 8 mm in diameter. Seed not seen.

Distribution and ecology

This endemic species is found in a broad ecological range, quite commonly scattered in several places on the main island ‘Grande-Terre’ ( Fig. 7 ), an epiphyte in humid or gallery forest. It grows from near sea level (10 m) to 900 m.

Taxonomic notes

In New Caledonia, in the sect. Grastidium, D. crassifolium is the only species to have parts of the perianth rounded at the apex. Dendrobium crassifolium has the thickest leaves of the graminoid New Caledonian Dendrobium , it is also the only species having vascular bundles in two lines (vs one), more than 32 vascular bundles (vs <30), and the largest vascular bundle with diameter <½ the thickness of the leaf blade (vs> ¾ the thickness).

Phenology

Flowering probably throughout the year (not observed in April).

IUCN status

The species is common in New Caledonia and was evaluated as Least Concern (LC) by the New Caledonian Red List Authority.

Figures

Fig. 1. (see full caption on page 5)

Fig. 5. Stomata (SEM). A–B. Type I: D. camaridiorum Rchb.f. (H.S. MacKee 14228). C. Type I: D. butinii M.Pignal & Munzinger sp. nov. (M. Pignal 2384). D. Type II: D. butinii M.Pignal & Munzinger sp. nov. (M. Pignal 2384). E. Type I: D. crassifolium Schltr. (H.S. MacKee 43781). F. Type II: D. crassifolium Schltr. (H.S. MacKee 43781). G. Type II: D. letocartiorum Munzinger & M.Pignal sp. nov. (H.S. MacKee 37760). H. Type II: D. unicarinatum Kores (H.S. MacKee 36986). Scale bars = 10 μm.

Fig. 7. Distribution of D. crassifolium Schltr., based on herbarium specimens (●) and field observations ().