Marsdenia kuniensis Meve, Gâteblé & Liede, 2018

Meve, Ulrich, Gâteblé, Gildas & Liede-Schumann, Sigrid, 2018, Two new species from the Ile des Pins (New Caledonia), and a not so new species from Grande Terre (New Caledonia), Phytotaxa 349 (3), pp. 201-213 : 206-208

Marsdenia kuniensis Meve, Gâteblé & Liede , sp. nov. ( Fig. 1C, D ; 4 ; 5 )

TYPE: New Caledonia, Ile des Pins , Sentier entre baie d´Oro et baie d´Upi, plant cultivated at SRA Saint-Louis, Dec 20, 2017, G. Gâteblé & J.Ounémoa 1001 (holotype P; isotypes K, MEL, MPU, NOU, UBT) .

Diagnosis: In habit like Marsdenia dognyensis but differing in the shape of the upper rim of the corolla tube that is fleshy and protrudes inwardly to create a suburceolate flower tube that strictly encloses the corona (vs. corolla tube more open, not explicitly fleshy and not strictly enclosing the corona in M. dognyensis ); the white to rose-coloured corolla (vs. purple red to purple brown in M. dognyensis ); protruding staminal corona lobes broader than long (vs. laminar and longer than broad in M. dognyensis );the mouth of guide rails not surmounting the bases of corona lobes (vs. surmounting the bases of corona lobes in M. dognyensis ), and a narrowly oblong corpusculum, c. 220 x 85 μm (vs. ovoid, c. 280 x 120 μm in M. dognyensis ).

Plants ascending, twining to 4–6 m high, sparsely branched, stoloniferous. Shoots perennial, herbaceous, pilose allover with erect, 500–1000 μm long trichomes; internodes 5–15 cm long, 2–3 mm diam. Latex white. Leaves with 10–25 mm long petiole, 4–5 colleters at the base of the lamina in conjunction to the petiole, colleters ovoid with acute tip; lamina herbaceous, 6–14 x 3–6 cm, ovate, basally cordate (except for neotenic shoots), apically acuminate with acumen 6–10 mm long, scattered over the whole surface with erect 450–600 μm long, often brownish trichomes, discolorous, adaxially green, glossy, abaxially bright green, with prominent, densely pilose rachis. Inflorescences always one per node, extra-axillary, sciadioidal or bostrychoid, occ. with basal dichasium, 4–12-flowered, 1–4 flowers open at time. Peduncles 1–5 mm long, more or less covered over the whole surface with erect, up 800 μm long trichomes. Flowers with floral bracts c. 0.5 x 0.2 mm, triangular, densely covered with trichomes. Pedicels 3–6 mm long, scatteredly covered with erect, c. 300 μm long trichomes. Floral buds 4–5 x 3–3.5 mm, subspherical to ovoid. Calyx entirely free, sepals c. 2.5 x 2.5 mm, subcircular, ciliate, abaxially glabrous or with trichomes. Corolla broadly campanulate to suburceolate, abaxially glabrous, whitish green; tube c. 2 mm long, c. 3 mm diam., mouth of tube fleshy, protruding, bearded, trichomes c. 0.6 mm long, spreading horizontally, hiding access to tube; lobes fused for about half of total corolla length, oblong, 2–2.5 x 2–2.5 mm, straight, patent, apically obtuse, ciliate, adaxially white to rose. Gynostegial corona of free staminal lobes broader than long, c. 1 x 1.2 mm long, much shorter than the gynostegium, broadly deltoid, fleshy, protruding, with entire margins. Gynostegium 1.4–1.6 mm long, 1.4–1.6 mm diam., (sub)sessile, with round nectar cavities below the mouth of guide rails; anthers subrectangular, abaxially planar; anther wings (guide rail) c. 500 μm long, shorter than the partially circumfluent corona lobes consisting of distal and proximal ridge, oblique to 30°, anther wings of adjacent anthers divergent towards the base; connective appendages c. 700 x 500 μm, triangular, narrower than the stamen, appressed to style-head. Pollinarium: corpusculum c. 220 x c. 85 μm, narrowly oblong; caudicles c. 200 x 35 μm, (sub-)basally inserted at the corpusculum, linear, sligthly bent downwards; pollinia subapically attached to the caudicles, erect, c. 400 x c. 150 μm, round in cross-section, oblongoid. Style-head c. 2 mm long, c. 1 mm diam.; upper part c. 1.4 mm long, conical. Follicles one per flower, pendulous, c. 50–60 x 15–20 mm, obclavate, round in cross-section, rugose, pubescent, very shortly beaked, tip rounded; seeds c. 8 × 4 mm, pear-shaped, dark brown, smooth on both sides, marginally with 0.4 mm wide wing with slightly crenate margin; coma 3.5–4 cm long.

Distribution and habitat: New Caledonia, endemic to Ile des Pins only.—Coastal rainforest, calcareous rocky soil. Altitude: 5– 30 m.

Phenology: ( Fig. 5 ) Flowers: December, March–April; Fruits: April, October.

Etymology: The name refers to the indigenous gallicized name (Kunié or Kounié) of the Ile des Pins. The native people call the island “Kwényii” or “Kwênyii”.

Provisional IUCN Status: The micro-endemic Marsdenia kuniensis is restricted to the coastal calcareous rainforests of Ile des Pins. Herbarium specimens are only available from the south part of the island but sterile plants have been observed by G. Gâteblé on 22 September 2017 in the forests around Gadji, in the north of the island. The species is not rare in the two localities but it is localized only in the richest and best preserved parts of the forests. The threats are quite low with a few feral pigs (Sus scropha) in both localities and low logging in the Gadji area. We then propose the “EN” category for this species using Red List criteria ( IUCN 2017) under the criterion B 1ab(iii,v)+2ab(iii,v).

Remarks: In habit, leaves and indumentum M. kuniensis cannot be distinguished from its sister-species M. dognyensis . Flower colour, however, makes separation possible, with the white to rose-coloured corolla that contrasts to the purple red to purple brown corolla of M. dognyensis . The shape of the corolla tube as well as the staminal corona lobes are most significant for distinguishing between the two closely related elements. There is more space between the (campanulate) corolla tube and the corona in M. dognyensis as in M. kuniensis , where the upper rim below the sinuses of the corolla lobes is fairly fleshy and protrudes inward to create a more suburceolate flower tube shape that strictly encloses the corona ( Fig. 4 B ). The corona lobes itself are broadly deltoid (broader than long), and thus differ much from the laminar ones (longer than broad) in M. dognyensis , which are also notched along the lower half with the lateral parts spreading wing-like. Also, the mouth of guide-rails are not surmounting the bases of corona lobes in M. kuniensis , but do so in M. dognyensis . The connective appendages are lanceolate and longer than the corona lobes in M. kuniensis , whereas they are deltoid, apically obtuse, and shorter than the corona lobes in M. dognyensis . Finally, the top of style-head is specifically long and pointed in M. kuniensis . Marsdenia kuniensis presumably evolved in isolation on the Ile des Pins, to which it is strictly endemic.

Paratypic material:

Ile des Pins, Ilots Ouate et Koungouati, 0–10 m, Oct 13, 1966, MacKee 15838 ( P 04258631, P); Ile des Pins: Sentier entre baie d´Oro et baie d´Upi, 14 m, Apr 20, 2016, Gâteblé, Karnadi & Laudereau 754 ( NOU, UBT (in alc.)); Ile des Pins, Sentier entre baie d´Oro et baie d´Upi, plant cultivated at SRA Saint-Louis, Mar 21, 2017, Gâteblé 854 ( NOU).

Figures

FIGURE 1. A, B, Heterostemma bicanthaceum (A, Ile des Pins, Sentier Oro-Upi, 20-04-16, GG756, photo: G. Gâteblé; B, Ile des Pins, 20-04-2016, photo: C. Laudereau). C, D, Marsdenia kuniensis (C, Ile des Pins, Sentier Oro-Upi, 20 Apr 2016, GG754). E, F, Marsdenia neomicrostoma (Grande Terre, Tinip, 08 Mar 2007). (Photo: A,C, E–F: G. Gâteblé; B, D: C. Laudereau).

FIGURE 4. Marsdenia kuniensis Meve, Gâteblé & Liede. A, leafy branch; B, flower in lateral view with parts cut away to expose gynostegium with corona; C, sepal, abaxial view; D, anther with corona lobe attached; E, pollinarium; F, style-head. All from Gâteblé et al. 754 (Drawn by U.Meve).

FIGURE 5. Distribution of Marsdenia kuniensis Meve, Gâteblé & Liede.