Rauvolfia sachetiae
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Ordo: Gentianales
Familia: Apocynaceae
Genus: Rauvolfia
Name
Rauvolfia sachetiae Fosberg, Smithsonian Contr. Bot. 47: 21, 1981. – Wikispecies link – Pensoft Profile
Type:
Marquesas Islands: Hiva Oa: dry crest above Taaoa, SW of village, 350 m, M.-H. Sachet 2115 (Holotype US!; Isotype BISH-598409!).
Description
Tree 6−10 m tall, trunk 20−25 cm in diam., bark furrowed, branches more or less horizontal, twigs and leaves in whorls of 3−4, entire plant glabrous, latex abundant; branchlets 4−6 mm in diam., proximal internodes to 9 cm long, distal ones 0.5−1 cm long toward end of season’s growth, terminal buds with abundant clear, brown resin. Leaves elliptic to broadly elliptic, 5.5−22 × 2.5−6.8 cm apex acute to obtuse, base acute to occasionally obtuse, slightly decurrent on petiole, glabrous, chartaceous, light to bright yellowish green when dried, secondary veins 12−15 on a side, brochidodromous, forming a wide angle with costa, secondary and tertiary veins prominulous on both surfaces; petioles 15−35 × 1−2 mm in diam. with 20−30 brown digitate, glandular colleters 0.5−1.2 mm long in each leaf axil. Inflorescences terminal, pseudoaxillary by displacement, compound cymes 3−6 × 8−12.5 cm including the corollas, peduncles verticellate, 1.5−3 cm long, 3−6 times ramified, branches open, widely divergent, ultimate branches trichotomous with central branch usually represented by a single pedicellate flower, most flowers early caducous from all but the most distal branches, each lateral branch subtended by a scale-like, ovate-triangular bract 1−1.5 × 1−1.5 mm, a bract pair subtending each lateral bud, axils of bracts glandular as those of leaves, pedicel of central flower 2−2.5 mm long, lateral buds of a triad subsessile, globose, tending to develop into a new triad with only the central flower of a triad developing to anthesis; calyx turbinate-campanulate, lobed almost to base, lobes 1.5−2 × 1.5−1.7 mm, imbricate, obtuse, margins thin; corolla yellow in bud, at anthesis cream colored, 12−14 mm long including limb, tube 9.5−14 × 1−1.5 mm in diam. medially, slightly dilated at apex and base, lobes slightly left-contorted, ovate, 2.5−3.5 × 2 mm, obtuse or rounded at apex, anthers narrowly ovate, somewhat bluntly acuminate, sagittate at base, subsessile, 1.5 mm long, inserted 1.5 mm below throat, a very few hairs around and below insertion on inside surface of corolla tube; ovary surrounded by cup-like nectary disk with minutely crenulate margin, carpels oblong, free distally, united in lower half, style glabrous, 7−9 mm long, style head thickened, cylindrical (not seen: floral description from Fosberg 1981[1]). Fruit subglobose to globose, 12−15 mm long, fleshy, turning black at maturity (at least when dry), apex rounded or emarginate, subtended by persistent spreading calyx. Seed 1 by abortion (only one mature fruit examined) 12 × 8 × 5 mm, 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, Hiva Oa, previously known only from a single tree at the type locality above Taaoa. In 2011 one dead trunk probably representing this species was found in a small gulch above Tanaeka valley, at around 430 m elevation (Butaud, pers. obs.).
Ecology
Dry secondary forest or shrubland with Casuarina.
Conservation status
Despite careful searches this species has not been found since the last collection was made at the type locality in 1977. In 2010 the area was observed to be overgrazed by goats and invaded by Syzygium cumini.(L.) Skeels (Butaud, pers. obs.). Rauvolfia sachetiaefalls into the Critically Endangered (CR) category, which designates species facing the highest risk of extinction in the wild. IUCN Red List Category: Critically Endangered (CR) B1a, b; B2a, B2b (i–iii): B1, extent of occurrence estimated to be less than 100 km2, and B1a, known to exist at only a single location; B1b (i-iii), continuing projected decline in (i) extent of occurrence, (ii) area of occupancy, and (iii) area, extent and quality of habitat; B2, area of occupancy estimated to be less than 10 km2, and B2a, a single population known. B2b (i–iii), continuing habitat decline inferred. The suitable habitat for Rauvolfia sachetiae on Hiva Oa (c. 315 km2) is indicated as an endangered environment, threatened by human activity (deforestation and fire), feral animals, and invasive plants, reducing the extent of the forest.
Specimens examined
Marquesas Islands: Hiva Oa: Ridge above Taaoa, SW of village, 350 m, 20 Nov 1974, Sachet & Decker 1885 (BISH, CBG, CHR, L, MO, NSW, P, PTBG, US), Taaoa, sur la presqu’île, versant SW, 350 m, 8 March 1977, Schäfer & Oliver 5293 (BISH, CBG, CHR, MO, NSW, PTBG, US).
Taxon Treatment
- Lorence, D; Butaud, J; 2011: A reassessment of Marquesan Ochrosia and Rauvolfia (Apocynaceae) with two new combinations PhytoKeys, 4: 95-107. doi
Other References
- ↑ Fosberg F (1981) Polynesian Plant Studies 6–18. Smithsonian Contributions to Botany 47:1-38. doi:10.5479/si.0081024X.47
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