Cyclosorus castaneus
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Illustration of Cyclosorus castaneus |
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| Cyclosorus castaneus | ||||||||||||
| ARSm. & Lorence |
Cyclosorus castaneus is a species of the genus Cyclosorus withinthe marsh fern family (Pteridaceae). It is only known from the island of Nuku Hiva , one of the Marquesas islands in the southern Pacific .
description
Cyclosorus castaneus is a perennial herbaceous plant . It grows as a terrestrial fern that forms an upright rhizome 15 to 60 centimeters long .
On each rhizome, the fronds stand together in groups of seven to ten. The reddish brown frond stems are 40 to 50 centimeters long and are covered with numerous reddish hairs, which are often curved.
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 three to five millimeters and a width of 0.3 to 0.5 millimeters. The stems are also sparsely covered with wart-like glands. At the transition from the stem to the actual frond, there are seven to ten pairs of reduced leaflets, which are 0.1 to 3.5 centimeters long, the largest of which can be three columns. The pairs of pinnate leaves are three to five centimeters apart.
The simply pinnate fronds reach a length of 50 to 70 centimeters without the receding uppermost leaflet. The largest leaflets are eleven to 16 centimeters long, between 1.5 and 2.0 centimeters wide and have scale-like, swollen and warty aerophores at their base . These aerophores can be up to four millimeters in size in young fronds. The base of the leaflets is not eyelet, while the tip is tailed to pointed. The pinnate leaves are lobed on two thirds to three quarters of their entire width, with the two to three millimeter long lobes being slightly sickle-shaped and having rounded tips. The leaf veins on the underside of the leaflets are covered with about 0.1 millimeter long, translucent hairs and with 0.3 to 1.5 millimeters long stronger and sickle-shaped hairs. Occasionally there are also a few light brown scales on the underside of the leaf, which are misshapen with a length of about two millimeters and a width of about 0.1 millimeters. On the leaflets there are yellowish glands , which stand close together on the underside of the leaflets, stand very loosely on the upper side of the leaflet or can be absent entirely. The leaf veins on the upper side of the leaf are covered with reddish and strong hairs, which are sickle-shaped with a length of up to one millimeter. In addition, sickle-like hairs that are 0.2 to 0.3 millimeters long can sometimes be found on the leaf veins.
The Sori stand in the middle of the leaf and are covered by a reddish brown to light brown, smooth or with a few 0.1 to 0.2 millimeter long hairs covered Indusium , which is 0.4 to 0.6 millimeters in size. They are usually absent from the tips of the leaflets. The sporangia have yellow glands.
Occurrence
Cyclosorus castaneus is endemic to the island of Nuku Hiva , one of the Marquesas islands in the southern Pacific . Cyclosorus castaneus is only known from three specimens, all of which were collected in the vicinity of the Ooumu peak on the Toovii plateau and probably belong to a single population . These specimens were all found in montane rainforests with a fern layer.
Systematics
The first description of Cyclosorus castaneus was made in 2011 by Alan Reid Smith and David H. Lorence in phytokeys . The three previously known specimens were previously assigned to Cyclosorus heterocarpus . The specific epithet castaneus refers to the chestnut brown hairs of the leaf central nerve on the underside of the leaf.
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 .
- ↑ Cyclosorus castaneus. In: The International Plant Names Index. www.ipni.org, accessed January 18, 2016 (English).
