Marsdenia neocaledonica Meve, Gâteblé & Liede, 2017

Meve, Ulrich, Gâteblé, Gildas & Liede-Schumann, Sigrid, 2017, Taxonomic novelties in Apocynaceae subfam. Asclepiadoideae from New Caledonia, Adansonia 39 (1), pp. 55-70 : 62-64

Marsdenia neocaledonica Meve, Gâteblé & Liede , sp. nov.

( Figs 1B, C ; 5 )

Similar to M.microstoma but differing in being erect to occasionally twining, sarmentose shrubs with densely and mostly distichously arranged, short, linear leaves, and campanulate flowers that do not exceed 3 mm in length.

TYPUS. — New Caledonia. Grande-Terre, North Prov., Koumac, Siounda , 200 m alt., in maquis on serpentine soil, 22.IV.1967, M.S.MacKee 16662 (holo-, P [ P00607336 ]!) .

PARATYPI. — New Caledonia. Grande-Terre, North Prov.: Kafeate , 12.XII.1950, M.Baumann-Bodenheim 9623 ( P04258708 , Z000052709 ) ; Pindai , 14.V.1992, T.Jaffré 3156 ( NOU017801 , P04237233) ; Vallée de la Koumac , 30 m, 19.IV.1967, H.S.MacKee 16598 (P04237234) ; Baaba, Pointe Sud-ouest, 5-20 m, 6.I.1971, H.S.MacKee 23212 (P04237231) ; Poum, Anse de Pouani , 5 m, 17.II.1971, H.S.MacKee 23336 ( NOU057837 , P04237232) ; Koné, Pinjen , 50 m, 25.IV.1971, H.S.MacKee 23654 (P04237228) ; Gomen, Cap Deverd , 20 m, 10.IV.1975, H.S.MacKee 30019 ( NOU057777 , P04237229) ; Plaine des Gaiacs , 20 m, 12.VIII.1977, H.S.MacKee 33588 ( NOU017800 , P04237230) ; Koumac, Siounda , 200 m, 13.V.1978, H.S.MacKee 35147 ( NOU017802 ,P04237225) ; Néhoué, Babouillat , 5 m, 9.V.1979, H.S.MacKee 36861 ( NOU017819 , P04237226) ; Koumac, Tangadiou , 50 m, 9.V.1979, H.S.MacKee 36874 (P04237227) ; Voh, Katepaik mountain, 4.IV. 2016, G.Gâteblé 760 (NOU) ; Ouaco, Néchoua , 100 m, 18.V.1981, H.S.MacKee 39095 ( NOU017818 , P04237224) ; Montagnes de Gomonen près Gatope , 1861-1867, E.Vieillard 2999 (P04237221, P04237222, P04237223) and E.Vieillard 3000 (P04237219, P04237220) .

The following sterile specimens probably also belong to M. neocaledonica , sp. nov.: Siouda , 20.I.2004, G. Dagostini 754, ( NOU001304 , P04526643) ; Poum , 13.XI.1990, I.H.Müller 186 (P04564507) ; Pagoumene , VIII.1967, A.Nothis 564 (P04593762) .

ETYMOLOGY. — While so many species of Marsdenia are endemic to New Caledonia, none has previously been named after the archipelago, where the new species is only found in the northwest of Grande-Terre.

DISTRIBUTION AND HABITAT. — New Caledonia. Grande-Terre northwest and Baaba island, North Prov. ( Fig. 3 ). On serpentine sites at the base of northwest ultramafic massifs or on serpentine veins in maquis close to the coast, receiving comparatively little precipitation (800 - 1200 mm /p.a.); 5-200 m altitude.

CONSERVATION STATUS. — This species has a northwest pattern of distribution at low altitudes on serpentine soils between Plaine des Gaiacs in the south and Baaba island in the north. There is no or very little nickel mining in these places and bush fires are the main issue for conservation of plants in those localities. With about ten localities, an EOO of 1075 km ² and an AOO of 44 km ², we are assigning a preliminary IUCN conservation status of “Near Threatened” using Red List criteria ( IUCN 2012).

DESCRIPTION

Plants

Erect to ascending shrubs, self-supporting or twining, 50- 70 cm high, sarmentose, runners warty.

Shoots

Perennial, herbaceous, basally slightly corky, sparsely covered with appressed, 180-200 µm long trichomes, glabrescent; internodes 5-15 mm long, 1-2 mm diam.

Latex

Colourless, sparse. Leaves

With petiole 2-5 mm long, densely and mostly distichously arranged, leaf blades coriaceous, with 2 colleters at the base, discolorous, 20-40 mm long (leaves supporting lateral shoots to 120 mm), 4-8 mm wide, elliptic, basally rounded, apically obtuse and mucronate, marginally revolute, adaxially and abaxially glabrous.

Inflorescences

Always one per node, growth continued beyond inflorescence, 3-7(-15)-flowered, all flowers open synchronously, sciadioidal. Peduncles 3-6 mm long, with sparse appressed trichomes, 180-200 µm long.

Flowers

With floral bracts c. 0.3 mm long, 0.2 mm wide at the base, ovate, with scattered trichomes. Pedicels 3-6 mm long, sparsely covered over the whole surface with flexuous trichomes, 180-200 µm long. Flower buds 20 × 15 mm when mature, conical.

Calyx

Entirely free, ciliate; lobes 0.6-0.8 mm long, c. 0.5 mm wide, ovate, apically acute.

Corolla

2-2.5 mm long, c. 4 mm diam., campanulate-rotate, abaxially yellow to purple, adaxially yellow, adaxially with 100-150 µm long trichomes concentrated on the tube and on the lateral parts of the lobes; lobes fused for about a third of total corolla length, 1-1.5 mm wide, patent, ovate, apically acute.

Gynostegial corona of free staminal lobes

Glabrous, 0.5-0.7 mm long, shorter than the gynostegium; lobes laminar, ovate, marginally thickened, apically recurved.

Gynostegium

0.9-1 mm long, 0.9-1 mm diam., elevated by a column of 350-400 µm length; anthers broader than long, rectangular, abaxially planar; anther wings 300-350 µm long, extending along the whole length of the anther; anther wings of adjacent anthers parallel to each other, in the same plane as the anther; connective appendages 375-400 × 300-350 µm, triangular, narrower than the stamen, slightly inflexed.

Pollinarium

Corpusculum c. 220 µm long, more than twice as long as broad, elliptic, margins of the corpuscular cleft sinuate; caudicles 70- 100 µm long, (sub-)basally inserted at the corpusculum, cylindrical, s-shaped, concave-convex, not thickened at the insertion of the pollinium; pollinia apically attached to the caudicles, erect, 250-270 × 60-80 µm, ovate in cross-section, oblongoid.

Style-head

0.5-0.7 mm long, 0.5-0.6 mm diam., forming a nose at the upper end of the corpusculum; upper part 0.4-0.5 mm long, longer than the lower part, conical.

Follicles

Always one per flower, 30-40 × 6-8 mm, obclavate, round in cross-section, acute, apically strongly beaked, wingless, medium brown, longitudinally grooved (when dry), glabrous, endocarp shining.

Seeds

6-6.5 × 3-3.5 mm, ovate, medium brown; seta and aseta side smooth, marginally with 0.5-0.6 mm wide wing with entire margin; coma 15-20 mm long.

REMARKS

Vegetatively with the linear leaves and florally with details such as gynostegium, corona and pollinarium structure a close relationship between M. neocaledonica , sp. nov. and M. mackeeorum , sp. nov. and M. microstoma is indicated. However, with 4 cm as maximum length, the leaves are shortest in M. neocaledonica , always surpassed in length in the other two species. The epithet “microstoma” indicates that the corolla of M. microstoma is urceolate (urn-shaped) and fused for more than half of its length, similar to the ovoid-urceolate corolla in M. mackeeorum , sp. nov. The corolla of M. neocaledonica , sp. nov., however, is open and subcampanulate with the lobes fused for around one third of total corolla length. Finally, the corona of M. neocaledonica , sp. nov. is expanded to include interstaminal portions as well, a character missing in the other two species.

Figures

FIG. 1. ─ A, Marsdenia kaalaensis Meve, Gâteblé & Liede, sp. nov., flowering at the type locality at Mt. Kaala, 20.X.2007 (Photo: J. Munzinger); B, C, Marsdenia neocaledonica Meve, Gâteblé & Liede, sp. nov., flowering in ultramafic maquis at Katepaik mountain, 4.V.2015 (Photo: Hervé Vandrot); D, Marsdenia paulforsteri Meve, Gâteblé & Liede, sp. nov. in habitat at Mt. Dzumac, 26.I.2010 (Photo: G. Gâteblé); E, Marsdenia paulforsteri, sp. nov. in cultivation (Photo: G. Gâteblé).

FIG. 5. ─ Marsdenia neocaledonica Meve, Gâteblé & Liede, sp. nov.: A, branch with inflorescences; B, leaf in cross-section; C, branch with open fruit; D, leaf in cross-section; E, flower in lateral view; F, gynostegium; G, pollinarium; H, style-head; I, seed. Drawings: A, B, E-H, U. Frensch from H.S. MacKee 16662; C, D, I, H.S. MacKee 36874 (P). Scale bars: A, C, 2 cm; B, 5 mm; D, 7.5 mm; E, 1 mm; F, 0.5 mm; G, 0.2 mm.

FIG. 3. ─ Distribution of the five new Neo-Caledonian Marsdenia R.Br. species.