Roscheria

Roscheria melanochaetes is an endemic to the Seychelles palm. It is the only species of the genus Roscheria.

• 4.1 Notes and references

Features

Roscheria melanochaetes is a small to medium-sized, single -stemmed palm. Young plants are spined, older little more armored. They are monoecious getrenntgeschlechtig ( monoecious ) and repeatedly flowering. The stem is erect, occupied bald and with conspicuous annular leaf scars. Sitting at the youthful leaf scar rings of black thorns, later are unarmed or with a few weak spines. At the base of the trunk sometimes grow aerial roots.

The chromosome number is 2n = 32

The leaves are pinnate irregular. The leaf sheaths are Roehrig and form a well-marked crown shaft. They are set with brown scales and armed with scattered, short, black spines. The thorns are most densely near the petiole base. The petiole is deeply grooved on the upper side, rounded at the bottom. At the base he is on the edge densely armed with short, black, slightly scraped thorns. The rachis is unarmed. The leaf blade is in young palms in whole or in two parts, divided irregularly in one to several -fold leaflets in older palms. Leaflets with a rib are pointed, those with multiple blunt or frayed. The upper leaf surface is glabrous, provided the underside with numerous tiny, dot-like scales and along the midrib conspicuous pubescence.

Inflorescences

The inflorescences are individually. First they put between the leaves ( interfoliär ), after leaf fall below the crown of leaves ( infrafoliär ). The inflorescence is strongly branched into three, rarely in the lower range up to four orders. The peduncle is long, winged crescent and at the base in cross section. The cover sheet is removed to some of the stem base. It is membranous to leathery, Roehrig, persistent, flattened and zweikielig. At the top there is shared shortly. It is unarmed and scattered covered with small scales. The bract on peduncle is slightly away from the cover sheet and is usually much longer than this. It is first Roehrig, then snaps over the majority of its length, and eventually falls off.

The inflorescence axis is significantly shorter than the stem. Your bracts are small, triangular and unobtrusive. The side axes of all orders are at the bottom of a short to long distance free of side axes and flowers. All axes are occupied with scales. The first-order page Achen are approximately double row ( subdistich ) that are proximal longer than the distal. The flower-bearing axes ( Rachillae ) are slender, rather short and flexible. They bear small bracts in a spiral arrangement in their armpits are in the mid - range Rachilla flowers triads, distally then paired and solitary flowers.

Flowers

The male flowers are very small and globose in bud stage. The three sepals are mostly free, imbricat, broad, triangular, keeled. The three petals are free, valvat and more than twice as long as the calyx. They are also wide and triangular. The six stamens have grown together at the base stamens. The free portion is short, broad, triangular. The anthers are round and small. The stamp rudiment is relatively large.

The female flowers are larger than the males. The three sepals are free, thick, imbricat, broad and round. The three petals are free, broad, triangular, the tips valvat short, otherwise imbricat. The six staminodes are tooth -shaped and fused at the bottom. The gynoecium is asymmetrical egg-shaped and has a fruit tray and an ovule. The scar is apical and three-lobed. The ovule is where the side.

Fruits

The fruit is small, spherical or ellipsoidal. When ripe it is red. The perianth remains to maturity get the scars radicals subbasal. The exocarp is smooth, provided the mesocarp very thin and with a layer of anastomosing fibers and numerous raphides. The endocarp is relatively thick, bone -like, smooth and with a basal germ opening (operculum ). The seed sits basal, has a rounded navel ( hilum ). The raphe is scarcely branched and anastomosing. The endosperm is deeply grooved ( ruminat ).

Dissemination and locations

The distribution area of Roscheria melanochaetes is limited to the Seychelles islands of Mahé and Silhouette. They are part of the undergrowth of mountain rain forests and very rare to find below 500 m above sea level. In about 750 meters above sea level, the type form on steep slopes in the understory of forests Northia pure stands.

System

The genus is placed Roscheria Verschaffeltiinae within the family Arecaceae in the subfamily Arecoideae, Tribe Areceae and subtribe. Her sister genus is Verschaffeltia.

In the World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew, just the way Roscheria melanochaetes is recognized.

The genus is by Albrecht Roscher (1836-1860), a German East Africa researcher, named.

Documents

• John Dransfield, Natalie W. Uhl, Conny B. Asmussen, William J. Baker, Madeline M. Harley, Carl E. Lewis: Genera palmarum. The Evolution and Classification of Palms. Second edition, Royal Botanic Gardens, Kew, 2008, ISBN 978-1-84246-182-2, pp. 615-618.