Ptychococcus

Ptychococcus is a native of New Guinea palm genus.

• 5.1 Notes and references

Features

The representatives are medium-sized, single -stemmed, monoecious palms. They are unarmed. The stem is erect and rather slender, has a brownish gray surface and is provided with distinct leaf scars. The outer bark of the trunk is very dense and is crossed by blackish fibers. The stems reach up to 26 m high with a base diameter of 25 cm. Young plants in the botanical gardens have only a diameter of 6 to 7 cm at 3 to 4 m high. This is unusual in palms, which otherwise exhibit no secondary growth. In Ptychococcus is believed that a diffuse secondary growth for thickening of older plants leads.

The chromosome number is 2n = 32

Adult plants usually bear six to 13 leaves. The leaves are spirally arranged, spreading their divided fiederig. The leaf sheaths form a striking crown shaft. The petiole is very short. At the top ( adaxial ) he has a groove, the bottom is rounded, both sides covered with dense hair. The rachis is adaxial initially flat, then furrowed towards the tip. The bottom is rounded. It is also densely hairy.

The leaflets are lanceolate, folded once, narrowed towards the tip, then tipped gestutz or light. The leaf margin is serrated. On both surfaces are reddish brown to pale scales at the bottom and along the veins denser. The midrib is well marked, the marginal ribs are large, transverse vascular bundles are not recognizable.

Inflorescences

The inflorescences are individually among the leaves ( infrafoliar ). They are stiff and usually there are several grouped below the crown shaft. In its heyday it be horizontal, crop maturity, they hang. In the lower part they are branched three times above less. All branches are densely scaly hairy and glabrous with time. The peduncle is short and stocky. The cover page is Roehrig, side beaked zweikielig and easily. It carries a balding hair. The bract on peduncle is similar to the previous sheet, but is not keeled. The inflorescence axis is longer than the stem and bears very short, roundish bracts, in whose axils the side branches and Rachillae sit. This, the flower-bearing axes, are rather short, sometimes zigzag and wear short roundish bracts, in which the large flowers are in triads.

Flowers

The male flowers are slightly asymmetrical. The three sepals are greenish, not adherent, imbricat and keeled towards the base. The three petals are not fused, valvat, oval and hairless or densely covered with small, membranous scales. There are numerous stamens, usually around 100 to 150, the outer filaments are easily fused with the petals. The filaments are creamy - white, short awl- shaped and in the bud straight, not curved. The anthers are dorsifix, ie the filaments put on to her back. The connective is tannic. The stamp rudiment is bottle -shaped, the neck is as long as the stamens. The pollen is ellipsoidal and asymmetric. The germ is opening a distal sulcus. The longest axis measures 46-66 microns.

The female flowers are ovoid, pale green and small flowering time than the male. The three sepals are not adherent, imbricat, roundish and sometimes covered with small hairs. The three petals are also not adherent, wide imbricat with short, thick valvaten tips. They are sometimes densely covered with scales. They cover themselves to anthesis fixed the gynoecium. There are three staminodes, which are combined in such a short half cup. The gynoecium is ovoid, unicompartmental and has a single ovule. A stylus is not differentiated. The ovule depends in the seed tray and a pentagon.

It is not known whether male or female flowers form nectar. Related palms with similar flower structure are pollinated by bees and other Hymenoptera.

Fruit and seeds

The fruit is ovoid, distinctly furrowed to 6 cm long and dry and edgy. At maturity it is orange to red. The perianth remains as a large cup of the fruit, the scar remains are somewhat eccentric. The exocarp is provided with short fiber bundles and Brachysklereiden. The mesocarp is orange, fleshy and contains tannin cells and vascular bundles without fiber sheaths. The endocarp has a large keel and is deeply furrowed. Between the grooves are three lateral and two ventral spine. The wall is hard and thick. The seed is five-lobed, according to the endocarp. The scar ( hilum ) is round and sits apical, the Raphe valve - branches are thin. The endosperm is homogeneous with a shallow edge union furrowing, or it is deeply furrowed.

The nature of the fruit spread is not known. In any case show the fruits of adaptations to dispersal by animals ( Zoochorie ). Terms of size, however, most frugivorous birds are excluded. Fallen fruits are to be eaten by cassowaries.

Dissemination and locations

The genus is restricted to New Guinea and the Bismarck Archipelago. The representatives grow in the lowlands as in the highlands. In the lowlands they occur mainly in the rain forest along rivers, in the highlands of mountain ridge. Both types are also cultivated around villages. Ptychococcus lepidotus is often planted in cemeteries. Some sites may also be due to brutalization, so that the natural range can no longer be distinguished from human-induced habitat today.

System

The genus Ptychococcus is placed in the subfamily Arecoideae, Tribe Areceae, subtribe Ptychospermatinae within the family Arecaceae.

Nine species have been described, Scott Zona has recognized only two species in its genus revision in 2005. He was followed by the World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew:

• Ptychococcus lepidotus
• Ptychococcus paradoxus

Use

The hard wood is processed into hunting bows and spears. Likewise, it is used as a timber.

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. 603-604.
• Scott Zona: A revision of Ptychococcus ( Arecaceae ). Systematic Botany, Volume 30, 2005, pp. 520-529.