Kadua tahuatensis
| Kadua tahuatensis | ||||||||||||
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| Kadua tahuatensis | ||||||||||||
| ( Lorence & J.Florence ) WLWagner & Lorence |
Kadua tahuatensis is a plant from the genus Kadua in the family of the Rubiaceae (Rubiaceae). It occurs endemically only on one island of the Marquesas Islands in the southern Pacific.
description
Vegetative characteristics
Kadua tahuatensis grows as a shrub that can reach heights of up to 2 meters. All shoots are hairless. The 0.4 to 0.6 centimeter thick branches have strongly compressed internodes . The smooth to furrowed bark is pale brown.
The constantly against arranged on the branches leaves are divided into a petiole and leaf blade. The strong and furrowed petiole is 0.2 to 0.5 inches long and 0.2 to 0.3 inches thick. The simple, paper-like to slightly leathery leaf blade is elliptical to elliptical-obovate with a length of 4.2 to 15 centimeters and a width of 2 to 8 centimeters. The base of the spade tapers to a point or a wedge shape, the occasionally pointed tip of the spade is blunt or rounded and the entire edge of the spread is thickened. Five to nine conspicuous lateral nerves branch off from each side of the leaf median nerve. The inter- and intrapetiolaren stipules are similar to the foliage leaves, are fused with the base of the petiole, thereby forming a cup-shaped sheath with a truncated tip. The leaf sheath is around 3 millimeters long and 5 to 6 millimeters wide.
Generative characteristics
The terminal zymose paniculate inflorescences are 5 to 6 inches long and 4.5 to 6 inches wide. The compressed inflorescence stalk is up to 2 inches long and 1.5 to 2 millimeters thick. The inflorescences contain 23 to 25 individual flowers. The flowers are on strong, compressed flower stalks, which are 2 to 3 millimeters long and 0.8 to 1.4 millimeters thick. The uppermost branches of the inflorescence each have two to three individual flowers.
The fourfold flowers are radial symmetry and probably dimorphic . The inverted-cone-shaped flower cup is 3 to millimeters long and 1.5 to 2 millimeters wide. The sepals are fused together to form a 2 to 3 millimeter long and 4 to 5 millimeter thick, bell-shaped calyx tube. The calyx lobes are oval-triangular in shape with a length of 1.5 to 2 millimeters and a width of 2 to 2.5 millimeters. The fleshy, pale green petals are fused together like a saucer. The corolla tube reaches a length of 1.3 to 1.6 centimeters and a diameter of 1.5 to 2 millimeters. The four bent-back crown lobes are linear-elongated with a length of 0.8 to 1 centimeters and a width of 0.15 to 0.2 centimeters and have a hook-shaped, bent-back appendage and dark purple edges at the top. The 3 to 3.5 millimeters long and 0.5 to 0.6 millimeters wide, somewhat prickly-pointed stamens are inserted close to the base of the corolla tube. The stylus is 1.1 to 1.2 centimeters long and the double-lobed scar is about 2.5 millimeters in size.
The capsule fruits are 1.2 to 2 centimeters long and 0.6 to 0.8 centimeters thick, top-shaped to obovate, top-shaped and stand on a sturdy, 0.3 to 0.8 centimeter long stem . The tip of the capsule fruits is divided into several segments. Each of the fruits contains several seeds that are 0.9 to 1.2 millimeters long. They are irregularly triangular or polygonal in shape and have a small, 0.1 to 0.3 millimeter wide wing. The seed coat has a net-like structure.
distribution
The natural range of Kadua tahuatensis is on the Marquesas Islands in the South Pacific . Kadua tahuatensis is an endemic species found only on the island of Tahuata . As far as known so far, the distribution area includes some high, south-east facing mountain slopes in the central mountain regions of the island.
Kadua tahuatensis thrives at altitudes of 780 to 835 meters. The species grows there in moist mountain forests and moist scrubland. In these forests and scrubland different types of grow Alsophila , Strip ferns ( Asplenium ), ribs ferns ( Blechnum ) Elaphoglossum , Cheirodendron , hibiscus ( Hibiscus ), Marsh clubmosses ( Lycopodiella ), iron wood ( Metrosideros ), sword fern ( Nephrolepis ), Reynoldsia and Weinmannia .
Taxonomy
It was first described as Hedyotis tahuatensis in 2000 by David H. Lorence and Jacques Florence in Adansonia . In 2005 Warren L. Wagner and David H. Lorence transferred the species as Kadua tahuatensis in Systematic Botany to the genus Kadua . The specific epithet tahuatensis refers to the range of the species.
Kadua tahuatensis is very similar to Kadua nukuhivensis in terms of its morphological appearance. Molecular studies have shown that they are sister species.
Individual evidence
- ↑ a b c d e f g h i David H. Lorence, Warren L. Wagner: Revision of Kadua (Rubiaceae) in the Marquesas Islands, French Polynesia, with description of the new species K. lichtlei . In: PhytoKeys . No. 4 , 2011, ISSN 1314-2003 , p. 125-138 , doi : 10.3897 / phytokeys.4.1601 .
- ^ Kadua tahuatensis at Tropicos.org. Missouri Botanical Garden, St. Louis, accessed December 21, 2016.
