Metroxylon

Sago palm ( Metroxylon sagu )

Metroxylon is a native to the Western Pacific palm genus. From now widespread throughout Southeast Asia sago palm ( Metroxylon sagu ) and other species is recovered strength. Metroxylon is the only genus of the subtribe Metroxylinae.

• 5.1 Notes and references

Features

The representatives are large, growing singly or in groups of tree-shaped palm trees. You are armed or unarmed and can once ( hapaxanth ) or several times flourish. The stem is upright and partially covered by the remaining after the death of the plant leaf bases. At the internodes sometimes arise from adventitious roots, which are usually thornlike. The bark of the trunk is hard, the marrow is soft and rich in starch.

The chromosome number is 2n = 26

The leaves are large, feathered and remain after the death of most of the plant ( Marzeszenz ). The leaf sheath tears down opposite the petiole, is reinforced or unreinforced with Teilwirteln of rather thin spines, which are united at the base and forming a kind of collar. The petiole is well trained, unreinforced or reinforced as the vagina. The stem top is furrowed in close to the trunk area, more rounded top, the bottom is rounded throughout. The rachis is similar to the blade handle, but at the top edges. The numerous leaflets are simply folded, linear and are available at regular intervals or in groups. In groups, they are then fan out and give the leaves a fiederiges appearance. Along the leaf margins and main veins are filled with inconspicuous, short spines. The middle ribs are clearly seen at the top.

Inflorescences

The inflorescences are twice branched and are, either between the leaves ( in the pleonanthen Metroxylon amicarum ) or grouped as a standing above the leaves, composite inflorescence. Here accordingly the lateral branches of a single inflorescence, it arises in the axil of a reduced foliage leaf or a high sheet. The peduncle is very short, the cover sheet is Roehrig, closely scheidig, zweikielig and bilobed. There are one to several -tube bracts on the inflorescence stalk. The inflorescence axis is considerably longer than the stem. The bracts on the axis are approximately double line ( distich ), they are Roehrig, closely scheidig are unarmed or rarely occupied with few spines.

The first-order lateral axes are horizontal to pendulous, each has a basal, röhriges, zweikieliges, bilobular blank cover page and approximately distich standing, closely differ -ended, high -tube sheets. All except the lowest one to three wearing kitten -like Rachillae. The Rachillae are cylindrical, with a short, free part, followed by a tight spiral of bracts. The bottom and top bracts are empty in the other dyads are of a small male and a similar hermaphroditic flower. In the bud stage, the dyad is obscured by dense pubescence, only Metroxylon amicarum the hair is sparse. The cover page of each dyad is Roehrig, zweikielig and with two triangular Lapen, and outside most densely hairy. The Brakteole is hairy zweikielig and dense.

Flowers

The male flowers open before the hermaphrodite. Your cup is Roehrig and ends with three triangular lobes. The crown is usually twice as long as the calyx, valvate about two-thirds of its length into three, smooth petals cut with triangular tips. The six stamens are at the base of the petals, their filaments are fleshy. The anthers are Medifix, elongated and latrors. In the center of the flower is a conical punch rudiment. The pollen is ellipsoidal and bisymmetrical. The colpi are disulcat equatorial.

The hermaphrodite flowers superficially resemble the male, but are fatter. Calyx, corolla and stamens are similar to those in the male flowers. However, the filaments are united at the lower end into a tube enclosing the ovary. The gynoecium consists of three carpels with one ovule. It is staffed round and with vertical rows of small scales. The stylus is conical and bears three scars edges. The ovules sit basal and are anatrop.

Fruit and seeds

The fruit is round, usually large and contains a seed. Apical scars are leftovers. The exocarp is covered with vertical rows of straw - colored to chestnut, rearward facing shed. The mesocarp is quite thick, corky until spongy. A endocarp is not formed. The seed is globular, sitting basal. At the top is the pressed hard. He is wrapped in a thin to thick sarcotesta. The endosperm is homogeneous. The embryo sits basal.

Dissemination and locations

The genus is native to East Malaysia's, the Solomon Islands, the New Hebrides, Samoa, Fiji and the Caroline Islands. For now widespread nature, the sago palm, New Guinea and the Moluccas is assumed to be original distribution area, but is now cultivated throughout Southeast Asia and also naturalized.

Most species grow in lowland swamps, where they often grow in groups with many individuals. Metroxylon amicarum also occurs in deep valleys and high in the mountains of Micronesia.

System

The genus Metroxylon is placed in the subfamily Calamoideae, Tribe Calameae within the family Arecaceae. You alone forms the subtribe Metroxylinae. Metroxylon is a monophyletic group.

In the World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew, the following types are recognized:

• Metroxylon amicarum
• Metroxylon paulcoxii
• Sago palm ( Metroxylon sagu )
• Metroxylon salomonense
• Metroxylon upoluense
• Metroxylon vitiense
• Metroxylon warburgii

Use

The two main uses of Metroxylon species is the extraction of sago (starch) from the pith of stems and the extraction of building materials for house construction: the leaves are used for thatching, from the split petioles braided walls are made.

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. 176-178.