Dendrobium butinii M.Pignal & Munzinger, 2020

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 : 13-17

Dendrobium butinii M.Pignal & Munzinger , sp. nov.

urn:lsid:ipni.org:names:77209475-1

Figs 1A, H, S , 3 C–D, 5 C–D, 8 , 9

Diagnosis

Dendrobium camaridiorum Rchb. f. affinis , sed planta gracilior foliis minoris fastigiatisque cum vagina minus sulcata , radicibus axillaribus, sepalis brevioris acuminatisque, petalis brevioris angustiorisque. Lobus medius labeli frimbriatus papillosusque.

Etymology

The species is dedicated to our good friend, Jean-Pierre Butin, an enthusiastic lover of botany, who first recognized and collected this taxon.

Type material

NEW CALEDONIA – Province Nord • s. loc.; 18 May 2001; fl.; J.-P. Butin s.n.; (original data: Mont Colnett 700 m, collected alive by J.P. Butin, 3 Oct. 1997); holotype: P[ P00157228 ]!; clonotype: P[ P00453885 ]! (see note) .

Paratypes

NEW CALEDONIA – Province Nord • Cultivated in Koné; 7 May 2003; fl.; J.-P. Butin s.n.; (original data: Mont Colnett, collected by J.P. Butin); P [ P00453886 ] • Mont Colnett ; 20°29′17″ S, 164°42′42″ E; alt. 690 m; 10 May 2003; fl. & fr.; J.-P. Butin s.n.; P [ P00777172 , P00777173 ] • Amoa GR Tchamba, Poindimié ; 20°59′2″ S, 165°13′55″ E; 13 Nov. 2016; fl. & fr.; C. Laudereau 133; NOU [ NOU090367 ] • Colnett Oua Ina, Pouébo ; 20°30′35″ S, 164°43′56″ E; 5 Jan. 2017; fr.; C. Laudereau 256; NOU [ NOU090368 ] • Colnett Oua Ina, Pouébo ; 20°30′38″ S, 164°44′0″ E; 2 Jan. 2018; C. Laudereau 663; NOU [ NOU090369 ] • Poindimié, Povila, Nérupaawé Pic Amoa ; 20°57′25″ S, 165°17′27″ E; 21 Oct. 2018; fl.; C. Laudereau 1061 & D. Szlachetko; NOU [ NOU090370 ] • Ouane Batch, Pouébo ; 20°30′35″ S, 164°43′56″ E; 23 Oct. 2018; fr.; C. Laudereau 1115 & D. Szlachetko; NOU [ NOU090371 ] • Mont Colnett, east side ; 20°29′13″ S, 164°42′39″ E; alt. 700 m; 3 Nov. 2003; fl. & fr.; A. Mouly 101; P [ P00777175 ] • Tchamba valley ; 21°0′13″ S, 165°14′49″ E; fr.; 23 Apr. 2004; M. Pignal 2350, J. Munzinger, J.P. Butin, C. Létocart, I. Létocart & D. Létocart; P [ P02288380 ] • Tchamba valley; 21°0′34″ S, 165°14′24″ E; fr.; 24 Apr. 2004; M. Pignal 2384, J. Munzinger, J.-P. Butin, C. Létocart, I. Létocart & D. Létocart; P [ P00777174 ] .

Description

Terrestrial or epiphytic herb with graminoid habit. Thin roots at the base of the plant, as well as along the stem, at the base of the nodes. Stems spindly 400 × 1.5–2 mm. Internodes 1–1.5 cm long. Sheaths of the dried leaves covering all of the stem, not deeply furrowed, the part opposite to the stem showing a beak-like extension. Leaves with narrow lamina, ca 2 mm wide at the base and 35–40 mm long. Lamina with a visible V-shaped depression printed around the lower third of the stem. Inflorescence 2-flowered, emerging from a small sessile sheath. Ovary resupinate. Flowers: sepals triangular, greenish, 9 × 3 mm, abruptly acuminate, acumen of the sepal 4 mm long. Petals linear, very narrow, greenish, ca 7 × 0.5 mm. Lip yellow-green, trilobate, with small short papillate hairs on edges. Lateral lobes 1 mm wide, weakly carinate, each carina surmounted by the same small papillate hairs. Median lobe cordiform, 3 mm wide, ending in a central clearly distinguishable carina, laterally fimbriate, each fibre covered with small papillate hairs, ending by a tuft of thick long hairs. Internal face of the column with longitudinal reddish macules, 3 mm height, mentum showing a right angle with the ovary, 3 mm. Ovary ca 2 mm long, on a peduncle 12 mm long. Fruit ellipsoid, ca 18 × 4 mm. Dried seed with transparent testa, 208 × 53 μm, fusiform with extremity and base attenuated. Extremity strongly spiralled. Hydrated seed elliptic sacciform. Cells cubic to polygonal, ca 65 × 4.6–6.6 μm, with spiral orientation. Edges thick, with spiral orientation, cellular walls smooth. Embryo spherical or elongate, about 8 μm in diameter.

Distribution and ecology

This endemic species has been located so far on one mountain (Mont Colnett) and in one valley (Tchamba) and appears restricted to humid forest of the North-East of the main island. Dendrobium butinii sp. nov. appears to occur in areas with the same ecological conditions as those of D. unicarinatum .

It can also occur in windy areas, as a lithophytic cushion plant on mossy micashists, in a dense population of cushion-like plants (Butin, pers. comm.). The species is known from 280 to 700 m elevation. The species has been observed also in the forest of Sailles (Thio) and Pénari (C. Laudereau, pers. comm.).

Taxonomic notes

The material studied that we attribute to D. butinii sp. nov. clearly does not correspond to D. minutiflorum Kraenzl. ( Kränzlin 1914: 84) , which was considered an insufficiently known species by Hallé (1977) and was based on a single collection (Sarasin 579) that was probably destroyed in Berlin. According to the original description ( Kränzlin 1914), D. minutiflorum has bilobed leaves that are 23 mm long and 6–7 mm wide, 2–3-flowered inflorescences, suggesting that this taxon would be closest to D. isochiloides Kraenzl. ( Kränzlin 1894: 334) (= Monanthos isochiloides (Kraenzl.) Rauschert in Rauschert 1983: 455 ) and D. erectifolium J.J.Sm. ( Smith 1908: 16) (= Monanthos erectifolius (J.J.Sm.) Rauschert in Rauschert 1983: 455 ). Hallé suggested this species might be related to members of sect. Grastidium, although the 3-flowered inflorescence would be very surprising inside this section. The ecological conditions in which the two taxa ( D. minutiflorum and D. butinii sp. nov.) occur are also different: D. minutiflorum was collected at Yaté in extreme SE New Caledonia, at low altitude (100 m) in an area with ultramafic soil, whereas D. butinii sp. nov. grows between 450 and 700 m at sites with sedimentary substrates.

Dendrobium butinii sp. nov. matches the characters of the “fourth group” so called by Hallé (1977), characterized by having leaves along the stem, internodes hidden by leaf sheaths that are not imbricate and 2-flowered inflorescences on the leafy stems, opposite the lamina and developing from a small, sessile sheath. In New Caledonia this morphological group is represented by three species: D. butinii sp. nov., D. crassifolium and D. camaridiorum . This group is also remarkable by the presence of a ‘V-like’ central imprint on the leaves, always clearly present in D. camaridiorum and D. crassifolium , sometimes less apparent in D. butinii sp. nov. ( Figs 1R , 8 ).

Dendrobium camaridiorum is the closest species to D. butinii sp. nov. Based on habit, D. butinii sp. nov. can be distinguished by its more spindly aspect, its smaller leaves, the presence of numerous adventive roots without adventive plantlets (‘keikis’) and its abruptly narrowed sepals.

Floral features, including the presence of papillose hairs on the lip and its fimbriate aspect, suggest a close affinity between D. butinii sp. nov. and D. crassifolium , although the hairs and fibres are much more developed in the latter species. Dendrobium butinii sp. nov. has thin leaves and vascular bundles in one line as D. camaridiorum , but differ by having vascular bundles <15 (vs> 22), midrib not prominent (vs prominent), largest bundles in position 3(4–5) (vs 5(–6)) and presence of supernumerary fibre bundles (vs absence). Dendrobium butinii sp. nov., D. camaridiorum and D. crassifolium were all observed by the authors growing together on a single tree trunk in the Tchamba valley in NE New Caledonia.

Phenology

Flowering and fructification periods need further observations. The fruits were observed from the field and in cultivation (in New Caledonia) in January, April to May, October to November. Flowering specimens were observed in January, April, May and October to November.

IUCN status

Even if uncommon, D. butinii sp. nov. was evaluated as Least Concern (LC) by the New Caledonian Red List Authority, because no specific threat to the species or its habitat is known.

Note

Unrecognised by the International Code of Nomenclature for algae, fungi, and plants ( Turland et al. 2018), the clonotype notion is used by numerous systematicians working on groups which can be cultivated. By ‘clonotype’ we designate here all material originated from the individual which provided the holotype and isotypes. Thus, the collector of a clonotype and the collection date can be different from those of the ‘type’ material. According to the Code, this is a paratype, but it can be genetically equated to an isotype; thus we believe the clonotype notion should be accepted by the Code.

Figures

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

Fig. 3. Seeds, opening on the right. A–B. D. camaridiorum Rchb.f. A. LM. B. SEM (H.S. MacKee 14228). C–D. D. butinii M.Pignal & Munzinger sp. nov. C. LM. D. SEM (M. Pignal 2384). E–G. D. letocartiorum Munzinger & M.Pignal sp. nov. E. SEM. F. LM. G. SEM (H.S. MacKee 37760). H–I. D. unicarinatum Kores. H. SEM (H.S. MacKee 36986). I. LM (H.S. MacKee 44925). Scale bars: A–F, H–I = 10 μm; G = 30 μm.

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.8. Dendrobium butiniiM.Pignal& Munzinger, sp. nov.Butins.n. A. Habit.B. Sheath.C. Inflorescence. D. Flower. E. Lip. F. Dorsal sepal. G. Petal. H. Lateral sepal. I. Column. J. Fruit, profile. K. Fruit, face. L. Seed. Scale bars: A, C = 1 cm, B, E–I = 2 mm, D = 1 mm, J–K = 5 mm, L = 3.5 μm (A–B, E–L, J.-P. Butin s.n. [P00157228], C–D from a picture of J.-P. Butin). Drawing by Agathe Haevermans.

Fig. 9. Distribution of D. butinii M.Pignal & Munzinger, sp. nov., based on herbarium specimens (●) and field observations (), ‘T’ indicates the type collection.