Oparanthus coriaceus
| Oparanthus coriaceus | ||||||||||||
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| Scientific name | ||||||||||||
| Oparanthus coriaceus | ||||||||||||
| ( F.Br. ) Sherff |
Oparanthus coriaceus is a species within the family of the daisy family (Asteraceae). This endemic occurs only on theisland of Rapa Iti in the southern Pacific , which belongs to the Austral Islands .
description
Vegetative characteristics
Oparanthus coriaceus grows as a shrub that can reach heights of 1 to 3 meters and trunk diameters of up to 2 centimeters. The brown bark is smooth. The soft wood is cream-colored.
The cross-opposite leaves on the branches are divided into a petiole and a leaf blade. The petiole is 2 to 4.5 inches long. The simple, very thick and leathery leaf blade is 4.5 to 12 centimeters long and 3 to 12 centimeters wide, elliptical to broad, obovate to almost circular. Occasionally, the leaf blades can split along the leaf median nerve. The base of the spreader is blunt, the tip of the spreader is pointed or blunt and the strongly thickened edge of the spreader is entire or occasionally slightly wavy. Several pairs of conspicuous lateral nerves branch off from each side of the leaf median nerve, and the conspicuous higher-order leaf veins run approximately parallel to the lateral nerves.
Inflorescences and flowers
Oparanthus coriaceus is single sexed ( monoecious ). The well-known flowering period extends over almost the entire year. The terminal, at first upright and later hanging, zymous total inflorescences consist of three, more rarely also of one or two cup-shaped partial inflorescences. The inflorescence stem, if present, is up to 0.3 inches long. The flower heads have a height of 0.9 to 1.5 centimeters and a diameter of 0.5 to 1.2 centimeters. In the bell-shaped involucre the six to eight bracts are arranged in an irregularly graduated row . The bracts are 0.45 to 0.8 inches long. The chaff leaves on the convex cup base are 0.6 to 0.9 centimeters long.
The functionally unisexual flowers are four-fold with a double flower envelope . The flower heads contain 6 to 13 functionally female florets (= ray florets) in a stepped up two rows and 12 to 16 functionally male florets (= disc florets). The petals of the ray florets are divided into a 0.37 to 0.4 centimeter long corolla tube and an approximately 0.12 centimeter long tongue, which is deeply three-lobed at its tip. The tubular flowers have a 0.38 to 0.4 centimeter long corolla tube and 0.2 to 0.22 centimeter long corolla lobes.
Fruits and seeds
The fertile achenes , which form in the ray-flowers, are roughly elliptical to elliptical in shape with a length of 0.4 to 0.6 centimeters and have two wings. The 0.01 to 0.03 centimeter wide wings have a smooth or ciliate edge, extend beyond the tip of the achenes and form a 0.2 to 0.25 centimeter long awn . The 0.6 to 0.7 cm long achenes that form in the tubular flowers are sterile and have one to two 0.15 to 0.3 cm long awns.
Occurrence and endangerment
The endemic Oparanthus coriaceus occurs only on the island of Rapa Iti , which belongs to the Austral Islands . It was designated as “least concern” in the IUCN 1998 red list of endangered species and should be reassessed.
Oparanthus coriaceus thrives at altitudes of 280 to 600 meters. It grows in damp forests and in the dense vegetation in the cloud zone, mostly on slopes, more rarely on rock faces. Various types of corokia , eurya and ironwoods ( metrosideros ) grow in these forests .
Systematics
It was first described as Chrysogonum coriaceum in 1935 by Forest Buffen Harkness Brown in Bulletin of the Bernice P. Bishop Museum. Honolulu . In 1937 Earl Edward Sherff transferred this species as Oparanthus coriaceus in Occasional Papers of Bernice Pauahi Bishop Museum of Polynesian Ethnology and Natural History to the genus Oparanthus . Another synonym for Oparanthus coriaceus (F.Br.) Sherff is Bidens tubuaiensis Stuessy .
Oparanthus coriaceus forms hybrids with Oparanthus rapensis, which occurs on the same island .
swell
- Robynn K. Shannon, Warren L. Wagner: Oparanthus (Asteraceae, Subtribe Coreopsidinae) Revisited . In: Allertonia . tape 7 , no. 4 , 1997, ISSN 0735-8032 , p. 273-295 .
Individual evidence
- ↑ a b c d e f g h i j Robynn K. Shannon, Warren L. Wagner: Oparanthus (Asteraceae, Subtribe Coreopsidinae) Revisited . In: Allertonia . tape 7 , no. 4 , 1997, ISSN 0735-8032 , p. 273-295 , JSTOR : 23190460 .
- ↑ a b DJ Crawford, M. Tadesse, ME Mort, RT Kimball, CP Randle: Coreopsideae . In: VA Funk, A. Susanna, TF Stuessy, RJ Bayer (Eds.): Systematics, evolution and biogeography of Compositae. International Association for Plant Taxonomy, Vienna 2009, p. 713–730 ( full text [PDF]).
- ↑ a b c Oparanthus coriaceus in the IUCN Red List of Threatened Species 2017.1. Listed by: J. Florence, 1998. Retrieved July 9, 2017.