Oparanthus teikiteetinii
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Leaves and inflorescences of Oparanthus teikiteetinii |
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| Oparanthus teikiteetinii | ||||||||||||
| ( J.Florence & Stuessy ) RKShannon & WLWagner |
Oparanthus teikiteetinii is a species within the family of the daisy family (Asteraceae). It is endemic tothe Marquesas in the southern Pacific .
description
Vegetative characteristics
Oparanthus teikiteetinii grows as a tree that can reach heights of up to 12 meters and trunk diameters of up to 0.35 meters. The bark is brown on young trees and turns gray with age, while the wood is cream-colored. The reddish brown bark of the young shoots is densely covered with coarse hair.
The cross-opposite leaves on the branches are divided into a petiole and a leaf blade. The leaf stalk, densely covered with rough hair, is 1.5 to 13 centimeters long and reaches a diameter of 0.6 to 2 centimeters. The simple, relatively thin leaf blade is ovoid to elliptical, sometimes also obovate, with a length of 5 to 24 centimeters and a width of 2.5 to 15 centimeters. Fresh leaves are coarsely hairy, especially on the underside of the leaf, but with increasing age the hairs thinning or the leaves are completely bare. The base of the blade is blunt, occasionally wedge-shaped or unevenly, the tip of the blade is pointed or blunt, rarely also spiky, the edge of the blade is usually entire, more rarely also toothed and pointed. Several pairs of lateral nerves branch off from each side of the leaf central nerve and the higher-order leaf veins form a network-like pattern.
Inflorescences and flowers
Oparanthus teikiteetinii is single sexed ( monoecious ) and the known flowering period extends from June to August and the month of December. The terminal, first upright and later hanging, zymic total inflorescences consist of one or three, rarely two cup-shaped partial inflorescences. The partial inflorescences are 1.6 to 2.5 centimeters in size and 1.4 to 2 centimeters in diameter. The rough hairy inflorescence stem is 2.5 to 7.3 inches long. In the bell-shaped involucre the twelve hairless bracts are arranged in three tiered rows , which are 0.7 to 1.2 centimeters long. The bracts on the convex cup base are 1 to 1.25 centimeters long.
The functionally unisexual flowers are four-fold with a double flower envelope . The flower heads contain 20 to 30 functionally female florets (= ray florets) in two to four stepped rows and 50 to 60 functionally male florets (= disc florets). The petals of the ray florets are divided into an approximately 0.7 centimeter long corolla tube and a 0.2 to 0.4 centimeter long tongue, which is flat at its tip, rarely also deep three to four times lobed. The tubular flowers have a corolla tube 0.6 to 0.8 centimeters long and corolla lobes about 0.35 centimeters long.
Fruits and seeds
The woody, fertile achenes , which form in the ray-flowers, are elliptically shaped with a length of 0.6 to 0.8 centimeters and have two wings. The 0.1 to 0.2 centimeter wide wings extend beyond the tip of the achenes and form an awn . The 0.8 to 0.9 centimeter long achenes which form in the tubular flowers are sterile and have two white awns.
Occurrence
The natural range of Oparanthus teikiteetinii is on the island of Nuku Hiva, which belongs to the Marquesas . The distribution area there includes the part of the Toovii plateau west of Mont Tekao .
Oparanthus teikiteetinii thrives at altitudes of 990 to 1050 meters. The species grows there in moderately moist to moist forests, mostly on steep slopes and in ravines. Various species of Crossostylis , Cyathea , Cyrtandra , Fagraea , Freycinetia , Macropiper , ironwoods ( Metrosideros ), Pipturus and crushed shrubs ( Psychotria ) grow in these forests .
Systematics
The first description as Bidens teikiteetinii was in 1988 by Jacques Florence and Tod Falor Stuessy in Bulletin du Muséum National d'Histoire Naturelle. Section B, Adansonia: Botanique Phytochemie . In 1997, Robynn K. Shannon and Warren L. Wagner transferred the species as Oparanthus teikiteetinii in Allertonia to the genus Oparanthus .
swell
- Oparanthus teikiteetinii. In: Flora of the Marquesas Islands. www.botany.si.edu/pacificislandbiodiversity/marquesasflora, accessed on April 30, 2017 (English).
Individual evidence
- ↑ a b c d e f g Oparanthus teikiteetinii. In: Flora of the Marquesas Islands. www.botany.si.edu/pacificislandbiodiversity/marquesasflora, accessed on April 30, 2017 (English).
- ↑ a b c Robynn K. Shannon, Warren L. Wagner: Oparanthus (Asteraceae, Subtribe Coreopsidinae) Revisited . In: Allertonia . tape 7 , no. 4 , 1997, ISSN 0735-8032 , p. 273-295 .
- ↑ Oparanthus teikiteetinii. In: The International Plant Names Index. www.ipni.org, accessed April 30, 2017 (English).
