Rauvolfia nukuhivensis (Fosberg & Sachet) Lorence & Butaud, 2011

Lorence, David H. & Butaud, Jean-Francois, 2011, A reassessment of Marquesan Ochrosia and Rauvolfia (Apocynaceae) with two new combinations, PhytoKeys 4, pp. 95-107 : 101

Rauvolfia nukuhivensis (Fosberg & Sachet) Lorence & Butaud comb. nov. Figs 2A, B, C

Ochrosia nukuhivensis Fosberg & Sachet, Micronesica 8: 48, 1972. [Basionym]

Type.

Marquesas Islands: Nuku Hiva: without precise locality, ca. 1000 m, 20 June 1921, F. B. H. Brown 432(Holotype BISH-500695!).

Description.

Tree 8-15 m tall, trunk 40-50 cm in diam., bark furrowed, pale orange to beige in color, leafy branchlets 3-3.5 mm in diam., glabrous, bark wrinkled, brown, leafless branchlets 6 mm in diam., gray-brown, latex white. Leaves ternate, leaf axils and adjacent petiole bases with brown, glandular digitate colleters 1-2 mm long; blades narrowly ovate to narrowly elliptic or oblong-elliptic, 6-17.6 × 1.5-6.2 cm, base narrowly cuneate to cuneate, apex acute, chartaceous, glabrous, when fresh pale green, discolorous, margin slightly revolute, secondary veins 21-25 on each side, intersecondary and tertiary veins prominulous on both surfaces, petioles 12-36 × 1.2-1.5 mm, adaxially flattened. Inflorescences terminal, displaced by terminal shoot growth, 5-7 × 7-10 cm, including the verticellate peduncles 1.7-5.4 × 2 mm, branchlets slightly zigzag, glabrous, branching three to four times, ultimate branches trichotomous, bracteoles 1.5 mm long, triangular, acute; calyx total width distally 3.2-4 mm, calyx lobes 5, broadly triangular-ovate, 1.5-2 × 1.5-2 mm, obtuse at apex; corolla cream color when fresh, tube 8-13 mm long, lobes 2-3.5 × 2-2.5 mm, slightly contorted to the left, anthers 1.2-1.3 mm long, narrowly triangular-subulate, sagittate at base, ovary conical, 1.5 mm long, nectary disc annular, 0.4-0.5 mm long, style 5 mm long, stigma head cylindric, 0.4 mm long, with membranous collar at base. Fruit subglobose when mature, 12-15 mm in diam., fleshy, turning black at maturity, drupaceous with 1-3 seeds. Seeds compressed, obliquely oblong-ovoid, with one straight and one curved edge, base sub-truncate, apex diagonal from straight edge upward to a blunt point, sides coarsely and shallowly rugose.

Distribution.

Marquesas Islands, known only from Nuku Hiva between 198 and 627 m elevation.

Ecology.

Rauvolfia nukuhivensis is very rare and localized with fewer than 50 living trees currently known in valley or plateau dry forest with species of Cerbera , Ficus , Maytenus , Phyllanthus , Sapindus , and Xylosma . Currently known in the Terre-Deserte region in the valleys of Motuee, Hakaavao, Haahopu, Haatuatua, Hakaoa, Tapueahu and Uea, and on the plateaus of Tohuahee, Vaiteheii, Maauu, and Putata. As many dead trees as living trees are known. Formerly known from the north coast of Nuku Hiva, between the Haataivea peninsula and behind Aakapa village.

Conservation status.

The suitable habitat for Rauvolfia nukuhivensis on Nuku Hiva (c. 340 km2) is indicated as an endangered environment, threatened by human activity (deforestation, exploitation for leaves and bark), feral animals, and invasive plants, reducing the extent of the forest. Following the criteria and categories of IUCN (2001) IUCN Red List Category: Critically Endangered (CR) B1a, B1b (i-iii), D; B1, extent of occurrence estimated to be less than 100 km2, and B1a, severely fragmented (several small subpopulations); B1b (i-iii), continuing projected decline in (i) extent of occurrence, (ii) area of occupancy, and (iii) area, extent, and quality of habitat; D population size estimated to number fewer than 50 mature individuals (fewer than 50 total individuals).

Specimens examined.

Marquesas Islands: Nuku Hiva: Tapueahu (labels erroneously says Matatekouaehi) Valley, 650 ft. (198 m), 1 July 1988, Perlman 10014 (AD, BISH, K, MO, MU, P, PAP, PTBG, US); Terre Déserte, branche gauche de la moyenne vallée de la Baie Marquisienne, face au Keiaki, 340 m, 30 July 1987, Florence 8434 (BISH, PAP, US); broad interfluve above Uea Valley, near Baie Marquisienne, 20 Apr. 1964, Decker 2046 (US); Ivipuovoteahi, NO de Keiaki, 400 m, 8°55' S, 140°12' W, February 1987, Jourdan 128 (PAP); Terre Deserte, Pipiheihe, 400 m, 8 April 1989, Toutain 4275 (PAP); Plateau de Maauu, au Sud du deuxième vallon de la forêt naturelle, 456 m, 9 April 2004, Butaud 418 (PAP).

Discussion.

Collectors’ notes indicate the leaves and bark are used for traditional medicine, another factor likely contributing to the decline of this species. Since 2006, a conservation plan lead by the Environment Direction of French Polynesia was implemented, with conservation ex situ (seed collection and conservation plantings) and in situ (enclosure of several populations). Local name: tueiao