Pteris tahuataensis
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Illustration of Pteris tahuataensis |
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| Lorence & KRWood |
Pteris tahuataensis is a plant from the genus of pteris within the family of pteridaceae (Pteridaceae). It is only known from the type location on the island of Tahuata , which is one of the Marquesas Islands in the southern Pacific .
description
Pteris tahuataensis is a perennial herbaceous plant . It grows as a terrestrial or lithophytic fern . It forms a creeping to semi-upright, 2 to 5 centimeter long rhizome , which is covered with fine hair and has a diameter of 1 to 3 centimeters. The golden brown hairs on the rhizome are needle-shaped with a length of 0.1 to 0.25 centimeters.
On each rhizome there are hanging fronds in groups of 15 to 20, which are up to 35 to 125 centimeters long with the stem. The dark chestnut brown to straw yellow frond stems are about half as long as the fronds and around 0.4 centimeters thick. The frond stalks are furrowed on the top and covered with a few light brown scales at the base, which are linear to linear-lanceolate with a length of 3 to 5 millimeters and a width of 0.3 to 0.5 millimeters. The stems are also sparsely covered with wart-like glands.
The one to two-pinnate fronds are egg-shaped with a length of 18 to 65 centimeters and a width of 12 to 35 centimeters and contain five to seven pairs of almost oppositely arranged, parchment-like leaflets. The lowest one to three pairs of the non-articulated leaflets are up to 34 centimeters long, are one to two-fold pinnate and sit on the frond stalk or stand on a stalk up to 9 millimeters long. They have a blunt to truncated base, a pointed, pointed or wedge-shaped tip and a notched or serrated leaf margin. The base can also be eyed, have two to three pairs of sickle-shaped lobes or it can occasionally fan out into sickle-shaped pinnate lobes. These pinnate lobes are 5 to 13 centimeters long and 1.4 to 1.7 millimeters wide, with the longest being found on the lower side of the lowest pair of leaflets. The upper three to five pairs of simple leaflets are sickle-shaped with a length of up to 23 centimeters and sit on the frond stem. They have a blunt to truncated, sometimes also hollowed base, a wedge-shaped to pointed tip and a notched to serrated leaf margin. The single, terminal leaflet of the frond is 6.5 to 23 inches long and 1 to 2.5 inches wide. It is free-standing, but at the base it can also be fused with the pair of leaflets below. The pointed tip of the leaf is notched and the leaf veins, which are similar in color to the frond stem, are grooved on the upper side of the leaf, while they are rounded on the underside.
The Sori are covered by an olive-colored indusium and together with this they grow to a size of 0.5 to 0.9 millimeters. They are usually absent from the tips of the leaflets. The spores are colored maroon.
Occurrence
Pteris tahuataensis is endemic to the island of Tahuata , one of the Marquesas Islands in the southern Pacific . Pteris tahuataensis has so far been found in three populations at altitudes of 418 to 914 meters. These populations are within semi-dry to moist woods and Busch countries where they are exposed to the wind rock walls of basalt , growing, from which water is released. The surrounding vegetation is, inter alia, Cerbera manghas , Crossostylis biflora , barbatum Cyclophyllum , Ficus prolixa , Freycinetia species, Leptochloa marquisensis , Metrosideros Collina , grantii Myrsine , Pandanus tectorius , Reynoldsia marchionensis , the washing walnut ( Sapindus saponaria ), Selliguea feeioides , the Lindenblättrigen Eibsch ( Talipariti tiliaceum ), Weinmannia marquesana , Xylosma suaveolens as well as various moss and lichen species .
Systematics
The first description of Pteris tahuataensis was made in 2011 by David H. Lorence and Kenneth Richard Wood in phytokeys , number 4, page 33. The specific epithet tahuataensis refers to the island Tahuata on which this species is endemic.
swell
- David H. Lorence, Warren L. Wagner, Kenneth R. Wood, Alan R. Smith: New pteridophyte species and combinations from the Marquesas Islands, French Polynesia . In: PhytoKeys . No. 4 , 2011, ISSN 1314-2003 , p. 5-51 , doi : 10.3897 / phytokeys.4.1602 .
Individual evidence
- ↑ a b c d e f David H. Lorence, Warren L. Wagner, Kenneth R. Wood, Alan R. Smith: New pteridophyte species and combinations from the Marquesas Islands, French Polynesia . In: PhytoKeys . No. 4 , 2011, ISSN 1314-2003 , p. 5-51 , doi : 10.3897 / phytokeys.4.1602 .
- ↑ Pteris tahuataensis. In: The International Plant Names Index. www.ipni.org, accessed January 14, 2016 (English).
