Oxalis simplicifolia
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Oxalis simplicifolia |
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| Lorence & WLWagner |
Oxalis simplicifolia is a plant from the genus sorrel ( Oxalis ) within the family of Oxalidaceae (Oxalidaceae). It is only known from the island of Ua Huka , which belongs to the Marquesas Islands in the southern Pacific .
description
Appearance and leaf
Oxalis simplicifolia grows as a perennial , woody herbaceous plant or as a subshrub and reaches heights of 20 to 50 centimeters. The sparsely branched stems are prostrate, spreading or upright. Young stems are sparsely hairy and bald over time. Older stems have a smooth, reddish brown to dark brown bark and are 2 to 3 millimeters thick. There are hairy tufts on the thickened base of the petioles.
The leaves are arranged spirally along the stem axis and are divided into a petiole and a leaf blade. The 2 to 4.5 centimeters long and 0.6 to 0.8 millimeters thick leaf stalk has a flattened cross section and is bare or covered with a few hairs. The simple, somewhat leathery and bald leaf blade is egg-shaped to broadly egg-shaped with a length of 1.5 to 4.7 centimeters and a width of 1.2 to 3.7 centimeters. The top of the blade is dark green and the underside yellow-green. The base of the spreader is blunt, rounded or trimmed, the tip of the spreader blunt and edged and the thin edges of the spreader are entire. The leaf surfaces are pinnate.
Inflorescence and flower
The lateral, but almost terminally on the branches, doldy inflorescences are 5 to 8 centimeters long and contain 5 to 13 flowers. The inflorescence ends in a single flower and in two 1.8 to 4 centimeters long inflorescence axes with two to six flowers each. The bracts are sparsely covered with needle-shaped hairs and trichomes and with a length of 1 to 2 millimeters and a width of 0.3 to 0.4 millimeters linear-subphrate. The inflorescence stalk is 4 to 8 inches long.
The hermaphroditic flowers are radial symmetry and five-fold with a double flower envelope . The five sepals are 5 to 7 millimeters long and 1.7 to 2 millimeters wide and approximately oblong-egg-shaped with a pointed upper end. Both the top and bottom of the sepals are covered with headed trichomes. The five yellow petals are 1 to 1.2 centimeters long and about 0.5 centimeters wide and approximately obovate to oblong-elliptical with a blunt or rounded upper end. There are two circles with five stamens each, the longer 7 to 8 millimeters and the shorter 5.5 to 6 millimeters long. The stamens have grown together at their base. The kidney to almost spherical anthers are 0.4 to 0.5 millimeters in size. The gynoecium is 1 to 1.4 centimeters long and has a length 6 to 7 mm, ovoid to cylindrical ovary , five 1 to 2.5 millimeters long stylus and a slightly thickened, warty scar on. The question of whether heterostyly , i.e. different flower morphs, occur with Oxalis simplicifolia as with many other Oxalis species cannot be answered unequivocally according to the current state of knowledge, since all specimens collected and examined so far had the same flower morph.
Fruits and seeds
The oval-cylindrical, smooth capsule fruits are 10 to 11 millimeters long and 2 to 2.5 millimeters thick. At maturity, they are straight and not twisted. The fruits are hairy on the inside and each contain around 40 seeds. The shiny brown, wrinkled seeds are 0.8 to 0.9 millimeters long and about 0.5 millimeters in diameter, elliptical and somewhat flattened.
Occurrence
The natural range of Oxalis simplicifolia is on the Marquesas Islands in the southern Pacific . It only includes the island of Ua Huka , of which a population from the vicinity of Hanahouua and from the area around the two villages Hane and Hokatu is known.
Oxalis simplicifolia grows in the shrubby and herbaceous vegetation layer that has formed on steep basalt cliffs above moderately moist to moist forests. Freycinetia impavida , the linden-leaved marshmallow , Pandanus tectorius and Pisonia grandis , among others, grow in the forests . The species Oxalis gagneorum , which apparently grows in association with Oxalis simplicifolia , is also found at both locations .
Systematics
The first description of Oxalis simplicifolia was made in 2011 by David H. Lorence and Warren L. Wagner in phytokeys . The specific epithet simplicifolia refers to the simple, undivided leaves.
The systematic position of Oxalis simplicifolia within the genus Oxalis has not been clearly clarified, which is partly due to the fact that no DNA sequences could be obtained from the collected material. If one follows the monographs on the genus Oxalis published by Alicia Lourteig in 1994 and 2000, the species would be assigned to the subgenus Monoxalis , which so far comprises the two species Oxalis dichondrifolia and Oxalis robusta , which are native to the southwestern USA and Mexico . However, neither of the two species has a morphological similarity to Oxalis simplicifolia . Oxalis simplicifolia is possibly also related to the species Oxalis gagneorum , which is also native to the Marquesas .
swell
- David H. Lorence, Warren L. Wagner: Oxalis simplicifolia (Oxalidaceae), an unusual new unifoliolate species from the Marquesas Islands (French Polynesia) . In: PhytoKeys . No. 4 , 2011, ISSN 1314-2003 , p. 53-60 , doi : 10.3897 / phytokeys.4.1604 .
Individual evidence
- ↑ a b c d e f g h David H. Lorence, Warren L. Wagner: Oxalis simplicifolia (Oxalidaceae), an unusual new unifoliolate species from the Marquesas Islands (French Polynesia) . In: PhytoKeys . No. 4 , 2011, ISSN 1314-2003 , p. 53-60 , doi : 10.3897 / phytokeys.4.1604 .
- ↑ Oxalis simplicifolia. In: The International Plant Names Index. www.ipni.org, accessed April 17, 2016 (English).
