Oparanthus tiva
| Oparanthus tiva | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Leaves and flowers of Oparanthus tiva |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Oparanthus tiva | ||||||||||||
| WLWagner & Lorence |
Oparanthus tiva is a species within the family of the daisy family (Asteraceae). It is endemic tothe Marquesas in the southern Pacific .
description
Vegetative characteristics
Oparanthus tiva grows as a tree that reaches heights of 3 to 7 meters and a trunk diameter of up to 0.3 meters. A few buttress roots are often formed. The bark is brown while the wood is cream-colored. The young shoots have short internodes .
The cross-opposite leaves on the branches are divided into a petiole and a leaf blade. The petiole is 3 to 9 inches long. The simple, thin-leather leaf blade is ovate to broadly ovate in shape with a length of 10 to 19.3 centimeters and a width of 6 to 15.8 centimeters. Fresh leaves are often slimy and give off a turpentine odor. The base of the blade is usually blunt on unequal sides, occasionally also wedge-shaped, the tip of the blade is blunt to blunt, the edge of the blade is slightly serrated to almost entire. Several pairs of lateral nerves branch off from each side of the leaf median nerve, and on the underside of the leaf one can find domatia with small tufts of hair on the branches of the leaf veins.
Inflorescences and flowers
Oparanthus tiva is single-sexed ( monoecious ) and the known flowering time and fruit ripening includes July. The terminal, at first upright and later hanging, zymical total inflorescences consist of three cup-shaped partial inflorescences . The partial inflorescences are 1 to 2 centimeters in size and 0.9 to 1.4 centimeters in diameter. The inflorescence stem is 1.5 to 7.6 inches long. In the bell-shaped involucre , the seven to nine bracts are arranged in two tiered rows , which are 0.7 to 1.1 centimeters long. The bracts on the convex cup base are 1.2 to 1.3 inches long.
The functionally unisexual flowers are four-fold with a double flower envelope . The flower heads contain eight to ten functionally female, white ray florets (= ray florets) in one to three tiered rows and 18 to 20 functionally male, also white florets (= disc florets). The petals of the ray flowers are divided into a 0.3 to 0.4 centimeter long corolla tube and a 0.3 to 0.38 centimeter long tongue, which is slightly toothed at its tip. The tubular flowers have a 0.35 to 0.4 centimeter long corolla tube and about 0.3 centimeter long corolla lobes.
Fruits and seeds
The fertile achenes , which form in the ray-flowers, are approximately 0.8 to 0.9 centimeters long and approximately elliptical to lanceolate in shape and have two wings. The wing, which is up to 0.1 centimeters wide, has a smooth edge and extends beyond the tip of the achenes. The 1.2 to 1.3 centimeters long, linearly shaped achenes which form in the tubular flowers are sterile .
Occurrence
The natural distribution area of Oparanthus tiva is on the island of Tahuata, which belongs to the Marquesas . The distribution area there includes the higher regions of the island.
Oparanthus tiva thrives at altitudes of 790 to 900 meters. The species grows there in low wet forests, mostly on windswept slopes and in gorges near summit regions. Various species of Alsophila , Crossostylis , Cyrtandra , Dicranopteris , Freycinetia , Gahnia , Hibiscus ( Hibiscus ), Macropiper , Marattia , ironwoods ( Metrosideros ), Morinda , Reynoldsia , crushed shrubs ( Psychotria ) and Weinmannia grow in these forests .
Systematics
It was first described as Oparanthus tiva in 2011 by Warren L. Wagner and David H. Lorence in PhytoKeys . The specific epithet tiva honors Steven P. Perlman, who discovered the species and is known in the Marquesas under the nickname Tiva.
swell
- Oparanthus hivoanus. In: Flora of the Marquesas Islands. www.botany.si.edu/pacificislandbiodiversity/marquesasflora, accessed on April 25, 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 tiva. In: The International Plant Names Index. www.ipni.org, accessed April 28, 2017 .
