Rauvolfia sachetiae
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Part of the isotype of Rauvolfia sachetiae with leaves and inflorescence |
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Rauvolfia sachetiae is a species of plant from the subfamily of the Rauvolfioideae in the dog venom family(Apocynaceae). It is endemic to the island of Hiva Oa on the Marquesas Islands in the southern Pacific .
description
Vegetative characteristics
Rauvolfia sachetiae grows as a tree that can reach heights of growth of 6 to 10 meters and a diameter of 20 to 25 centimeters at chest height . The bark is furrowed. The branches go more or less straight from the tree. The branches, 0.4 to 0.6 centimeters thick, are arranged on the branches in threes or quadruples . The internodes of the branches are up to 9 inches long. Rauvolfia sachetiae does not form a milky sap .
The leaves are divided into a petiole and a leaf blade. Twenty to thirty brown hairs, 0.5 to 1.2 millimeters long, are found on the leaf axis. The petiole is 1.5 to 3.5 inches long and 1 to 2 millimeters thick. The simple, bare and parchment-like leaf blade is elliptical to broadly elliptical with a length of 5.5 to 22 centimeters and a width of 2.5 to 6.8 centimeters. The base of the spade is pointed or blunt and the tip of the spade is also pointed or blunt. The dried leaf blade is yellowish-green in color. 12 to 15 lateral veins branch off from each side of the leaf median nerve .
Generative characteristics
At the end of a 1.5 to 3 centimeter long inflorescence stem stand trichotomously branched, zymous inflorescences , which are 3 to 6 centimeters long and 8 to 12.5 centimeters wide. The scale-like bracts are ovate-triangular with a length and width of 1 to 1.5 millimeters.
The hermaphroditic flowers are radial symmetry and five-fold with a double flower envelope . The five sepals are only fused together at their base in a circular or bell-shaped manner. The five calyx lobes, overlapping like roof tiles, are 1.5 to 2 millimeters long and 1.5 to 1.7 millimeters wide and have a blunt upper end. The cream-colored petals are fused to form a calyx tube 0.95 to 1.4 centimeters long and 1 to 1.5 millimeters wide. The egg-shaped, 2.5 to 3.5 millimeters long and around 2 millimeters wide calyx lobes overlap slightly to the left. The carpels are surrounded by a cup-like nectarium with a finely notched edge. The elongated carpels are fused together in the lower half. The 7 to 9 millimeter long, bald stylus ends in a thickened, cylindrical scar .
The fleshy drupes, black when ripe, are almost spherical to spherical with a diameter of 1.2 to 1.5 centimeters. So far, only one ripe fruit has been examined which contained an elongated egg-shaped seed with a length of around 1.2 centimeters, a width of around 0.8 centimeters and a thickness of around 0.5 centimeters.
Occurrence
Rauvolfia sachetiae is endemic to the island of Hiva Oa on the Marquesas Islands in the southern Pacific . This species is only known from a single tree population , from which Marie-Hélène Sachet collected the type material in 1977 and which later became extinct. This population was on an elevation southwest of the village of Taaoa and could not be found when it was inspected again in 2010. In 2011, a dead tree stump was found by Jean-François Butaud in a ravine near the town of Tanaeka , which may also be attributed to Rauvolfia sachetiae .
Rauvolfia sachetiae grows in dry secondary forests or scrubland together with various types of casuarina ( Casuarina ).
Taxonomy
It was first described as Rauvolfia sachetiae in 1981 by Francis Raymond Fosberg in Smithsonian Contributions to Botany .
literature
- David H. Lorence, Jean-François Butaud: A reassessment of Marquesan Ochrosia and Rauvolfia (Apocynaceae) with two new combinations . In: PhytoKeys . No. 4 , 2011, ISSN 1314-2003 , p. 95-107 , doi : 10.3897 / phytokeys.4.1599 .
Individual evidence
- ↑ a b c d e f David H. Lorence, Jean-François Butaud: A reassessment of Marquesan Ochrosia and Rauvolfia (Apocynaceae) with two new combinations . In: PhytoKeys . No. 4 , 2011, ISSN 1314-2003 , p. 95-107 , doi : 10.3897 / phytokeys.4.1599 .
- ↑ Rauvolfia sachetiae. In: The International Plant Names Index. www.ipni.org, accessed July 7, 2016 (English).
