Trachycarpus geminisectus
| Trachycarpus geminisectus | ||||||||||||
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| Scientific name | ||||||||||||
| Trachycarpus geminisectus | ||||||||||||
| Spanner , Gibbons , VDNguyen & TPAnh |
Trachycarpus geminisectus belongs to the subfamily Coryphoideae in the palm family (Arecaceae).
history
Trachycarpus geminisectus was discovered in 1999 in the Sino-Vietnamese border area and was initially thought to be a Guihaia species. It was first described in 2003 by T. Spanner, M. Gibbons, VD Nguyen and TP Anh. The Latin epithet geminisectus means "with twin segments" and refers to the feature that the leaf segments of this palm species are usually connected in pairs over their entire length.
Occurrence
Trachycarpus geminisectus is a species similar to T. princeps and originates from the north of Vietnam, where it occurs in the provinces of Hà Giang (Quan Ba district) and Cao Bằng (Bao Lac district).
Trachycarpus geminisectus grows in Vietnam in the provinces of Hà Giang and Cao Bằng in primary, closed rainforests or in secondary, low, moist, mossy forests on steep slopes and along karst mountain ridges at altitudes between 1,100 and 1,600 meters, where they compete with conifers such as Cypresses ( Cupressus ), yew trees ( Taxus ), Nageia , Pseudotsuga , broad-leaved trees such as rhododendron species, some Lauraceae and Rosaceae species as well as other palm trees such as Plectocomia and large Caryota grow in the immediate vicinity. Even if it has not yet been discovered there, it seems very likely that Trachycarpus geminisectus is also found on the other side of the border in the Chinese Autonomous Region of Guangxi . However, there is only little reliable information about the actual distribution area of this species, so that no conclusive statement can be made about it. In the areas mentioned, however, it is apparently to be found quite often in the mountain ranges there. However, their natural habitat is mostly steep and inaccessible.
description
Like all Trachycarpus species, it is single-stemmed. The trunk reaches a height of 1 to 2 meters and is surrounded by permanent, fibrous leaf sheaths , which have a diameter of about 25 cm.
The leaves form a loose and very open crown and old, dried up leaves form a kind of loose cape around the trunk below the leaf crown. The leaf sheaths consist of very coarse, dark brown and very persistent fibers, which are occasionally covered with light brown scales, with the exposed parts of the leaf sheath being divided into stiff, wire-like threads.
leaves
The petioles are about 85 cm long, slender, about 1.4 cm wide and 0.9 cm thick, measured roughly in the middle part of the petiolus . The leaf stalks are very robust, stiff and flat on the top, as well as triangular in cross-section and with a light yellow stripe on the underside, which merges into orange towards the base. They are hairless and have tiny teeth around the edges. The hastula is small and triangular at 1.5 cm. The rachis extends slightly into the leaf and thus forms a weak midrib.
The leaf is fan-shaped, ¾ to completely circular, and about 85 cm long measured from the hastula, and 130 cm wide. The leaves are leathery, shiny dark green on the top, and covered with a thick white wax layer on the underside. The approximately 40 leaf segments divide the leaf regularly over a length of ¾ or deeper and are stiff and firm. They are connected along their entire length in groups of two, rarely three segments, with these tapering slightly in the last third towards the segment tips. They are arranged on one level, which results in an almost flat leaf profile. The central segments are about 85 cm long and in the middle part about 4 cm wide, which results in a width of about 8 cm for a typical double segment. On the last third to the segment tip, the segments taper, on the underside of which there is a thick and distinctive midrib is located. The lateral segments gradually get thinner and shorter up to a length of 50 cm by 1.5 cm wide. The segment tips are pointed, notched or slightly divided into two.
Inflorescences and flowers
Trachycarpus geminisectus is dioecious separately sexed ( diocesan ). The inflorescences arise between the leaves (interfoliar) and are triple branched. The male inflorescences are short, about 50 cm long. The stems are short and oval in cross section. The bracts of the inflorescences are keel-shaped, tubular at the base, slightly inflated and slightly coated with woolly hair. The inflorescences are pointed at the top. The bracts of the main branch of the inflorescences are very similar to those of the side branches. The side boxes (rachillae) of the inflorescences, which branch off even further, are short, about 3–6 cm long and thin. The flowers are close together, are spherical and have tiny bracts (bracts). The flowers measure about 3 mm in diameter, are yellow and fragrant. The sepals are oval-triangular, 2 mm long and fused with the flower base. The petals are oblong-rounded, twice as long as the sepals. There are six stamens that are longer than the petals. The stamens are slightly thickened on one side. The anthers ( anthers ) are arrow-shaped and blunt. The rudimentary carpels are about half as long as the stamens .
The female inflorescences are long, robust, stiff and splayed. The stem (peduncle) has an oval cross-section and the bracts are long and keel-shaped, tapering at the top. The side branches (rhachillae) are 7–13 cm long, fleshy and yellowish when bearing seeds. The flowers are spherical, 2–3 mm in diameter, yellow, fragrant, mostly solitary with tiny bracts (bracts). The sepals are 2 mm long, circular and the petals are oblong-rounded, 2.5 - 3 mm long. The sterile staminodes are very small. The carpels are thickened on one side and have a short conical stamp.
Fruits and seeds
The fruits of Trachycarpus geminisectus hang on short pedicels (pedicelli) and are reniform (kidney-shaped), wider than long with a thin, black epicarp . The mesocarp is also thin.
The seeds themselves are also reniform, broader than long, with a homogeneous endocarp . The first cotyledon (eophyll) is simple, narrow and folded.
Care in Central Europe
Since the availability of seeds of this species is very limited, Trachycarpus geminisectus has rarely been found in culture outside of its natural habitat . Its very large and attractive leaves with their broad leaf segments and their presumed frost tolerance could make them a popular ornamental plant for gardens in both the subtropical and temperate zones.