Oparanthus hivoanus
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Inflorescences of Oparanthus hivoanus |
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| Oparanthus hivoanus | ||||||||||||
| ( O.Deg. & Sherff ) RKShannon & WLWagner |
Oparanthus hivoanus is a species within the family of the daisy family (Asteraceae). It is endemic tothe Marquesas in the southern Pacific .
description
Vegetative characteristics
Oparanthus hivoanus usually grows as a shrub that reaches heights of 0.5 to 2 meters. In protected locations, the species also grows as a small tree that can reach heights of up to 5 meters and trunk diameters of up to 0.2 meters. The bark is brown while the wood is cream-colored. The young shoots have very short internodes .
The cross-opposite leaves on the branches are divided into a petiole and a leaf blade. The leaf stalk is 1.5 to 5, on younger shoots up to 10 centimeters long and reaches a diameter of 0.2 to 0.8 centimeters. The simple, leathery leaf blade is egg-shaped to broadly egg-shaped with a length of 2.3 to 8, on young shoots up to 13 centimeters and a width of 1.3 to 4.5, on fresh shoots up to 11 centimeters. The base of the spreader is blunt, occasionally wedge-shaped or unevenly, the tip of the spreader is pointed, the edge of the spreader is sawn to almost the entire edge. 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 hivoanus is single-sexed ( monoecious ) and the known flowering period extends from January to September. The terminal, at first upright and later hanging, zymical total inflorescences consist of three cup-shaped partial inflorescences . The partial inflorescences are 0.9 to 1.3 centimeters and have a diameter of 0.7 to 1.2 centimeters. The inflorescence shaft is 0.5 to 3.5 inches long. The seven to eight bracts , which are 0.65 to 0.8 centimeters long, are arranged in two tiered rows in the bell-shaped involucre . The bracts on the convex cup base are 0.9 to 1.1 centimeters long.
The functionally unisexual flowers are four-fold with a double flower envelope . The flower heads contain eight to eleven functionally female florets (= ray florets) in one to three tiered rows and 20 functionally male florets (= disc florets). The petals of the ray florets are divided into a 0.3 to 0.4 centimeter long corolla tube and a 0.3 to 0.33 centimeter long tongue, which is slightly lobed or toothed at its tip. The tubular flowers have a corolla tube about 0.25 cm long and about 0.3 cm long corolla lobes.
Fruits and seeds
The woody, fertile achenes that form in the ray florets are approximately elliptical in shape with a length of at least 0.7 centimeters and have one or two narrow wings. The up to 0.1 centimeter wide wing has a smooth to slightly irregular edge and extends slightly beyond the tip of the achenes. The about 0.45 centimeter long achenes which form in the tubular flowers are sterile and occasionally white a wing.
Occurrence
The natural range of Oparanthus hivoanus is on the island of Hiva Oa, which belongs to the Marquesas . The distribution area there includes the western part of the island and extends over the Mont Temetiu and Mont Feani to Hanamenu .
Oparanthus hivoanus thrives at altitudes of 850 to 1200 meters. The species grows there in the cloud zone in bushy forests, mostly on windswept slopes and in summit regions. Various types of Cheirodendron , Crossostylis , Cyathea , Freycinetia , ironwoods ( Metrosideros ), Reynoldsia , fan flowers ( Scaevola ) and Weinmannia grow in these forests .
Systematics
It was first described as Bidens hivoana in 1964 by Otto Degener and Earl Edward Sherff in Botanical Gazette; Paper of Botanical Notes. Crawfordsville, IN, Chicago, IL . In 1997 Robynn K. Shannon and Warren L. Wagner transferred the species as Oparanthus hivoanus in Allertonia to the genus Oparanthus .
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 Oparanthus hivoanus. In: Flora of the Marquesas Islands. www.botany.si.edu/pacificislandbiodiversity/marquesasflora, accessed on April 25, 2017 (English).
- ^ A b 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 hivoanus. In: The International Plant Names Index. www.ipni.org, accessed April 25, 2017 (English).
