Oparanthus woodii
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Leaves and flowers of Oparanthus woodii |
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Oparanthus woodii is a species within the family of the daisy family (Asteraceae). It is endemic tothe Marquesas in the southern Pacific .
description
Vegetative characteristics
Oparanthus woodii grows as a moderately branched tree that reaches heights of 2 to 5 meters. A few buttress roots are often formed. The bark is brown. The wood is cream-colored. The young branches have short internodes .
The cross-opposite leaves on the branches are divided into a petiole and a leaf blade. The petiole is 3.5 to 6 inches long and is fused with other petioles at the base. The simple, thin-leather leaf blade is 11 to 23.1 centimeters long and 3.5 to 12.7 centimeters wide, elliptical to broadly elliptical-obovate. The base of the spreader is usually unevenly wedge-shaped, the tip of the spreader is rounded to truncated and the edge of the spreader is entire. Several pairs of lateral nerves branch off from each side of the leaf median nerve. On the underside of the leaf one finds hairless domatia on the branches of the leaf veins.
Inflorescences and flowers
Oparanthus woodii is single-sexed ( monoecious ) and the known flowering period includes June. The terminal, first upright and later hanging, zymic total inflorescences consist of a single cup-shaped partial inflorescence. The strong inflorescence stem is 0.3 to 1.5 inches long. The flower heads have a height of 2.2 to 3.5 centimeters and a diameter of 1.2 to 1.6 centimeters. In the bell-shaped involucre , the eight bracts are arranged in two tiered rows , which are broadly triangular with a length of 0.8 to 1.3 centimeters. The bottom of the cup is convex. The chaff leaves of the ray florets are 13 to 14 millimeters long and those of the tubular flowers are 12 to 13 millimeters long.
The functionally unisexual flowers are four-fold with a double flower envelope . The flower baskets contain about 18 to 22 functionally female ray- flowers (= ray-flowers) in two graduated rows and around 40 to 50 or more functionally male tubular flowers (= disc-shaped flowers). The petals of the ray florets are divided into a 0.75 to 0.8 centimeter long corolla tube and a 0.42 to 0.45 centimeter long tongue, which is two- to three-lobed at its upper end. The tubular flowers have a 0.63 to 0.66 centimeter long corolla tube and 0.44 to 0.54 centimeter long corolla lobes.
Fruits and seeds
The fertile achenes , which form in the ray-flowers, are elliptically shaped with a length of 0.5 to 0.6 centimeters and have two wings. The approximately 0.1 centimeter wide wings extend slightly beyond the tip of the achenes. The 1 to 1.1 centimeters long, linearly shaped achenes which form in the tubular flowers are sterile and have two awns .
Occurrence
Oparanthus woodii is endemic to the Marquesas island of Nuku Hiva . The distribution area there only includes the gorges of the Ooumu region in the upper Tapueahu valley.
Oparanthus woodii thrives at altitudes of 1060 to 1130 meters. Oparanthus woodii grows in moderately moist to moist mountain forests, mostly on steep slopes and in ravines. Various types of striped ferns ( Asplenium ), rib ferns ( Blechnum ), Cyrtandra , Freycinetia , Hypolepis , holly ( Ilex ), Melicope , ironwoods ( Metrosideros ) and Weinmannia grow in these forests .
Systematics
It was first described as Oparanthus woodii in 2011 by Warren L. Wagner and David H. Lorence in PhytoKeys . The specific epithet woodii honors the botanist Kenneth R. Wood , who collected the type material of this species.
swell
- Oparanthus woodii. In: Flora of the Marquesas Islands. www.botany.si.edu/pacificislandbiodiversity/marquesasflora, accessed on May 1, 2017 (English).
Individual evidence
- ↑ a b c d e f g h Warren L. Wagner, David H. Lorence: Two new Marquesan species of the southeastern Polynesian genus Oparanthus (Asteraceae, Coreopsidinae) . In: PhytoKeys . No. 4 , 2011, ISSN 1314-2003 , p. 129-148 , doi : 10.3897 / phytokeys.4.1603 .
- ↑ Oparanthus woodii. In: The International Plant Names Index. www.ipni.org, accessed May 1, 2017 .
