Ptychococcus
| Ptychococcus | ||||||||||||
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Ptychococcus paradoxus |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Ptychococcus | ||||||||||||
| Becc. |
Ptychococcus is a genus of palm that is nativeto New Guinea and Papuaia.
features
The representatives are medium-sized, single-stemmed, monözischen palms. You are unarmed. The trunk is upright and rather slender, has a brownish-gray surface and is marked with clear leaf scars . The outer bark of the trunk is very dense and has blackish fibers. The trunks reach a height of up to 26 m and a diameter of 25 cm. Young plants in botanical gardens only have a diameter of 6 to 7 cm at a height of 3 to 4 m. This is unusual in palms that otherwise do not show any secondary growth in thickness. In Ptychococcus it is suspected that a diffuse secondary growth in thickness leads to the thickening of older specimens.
The chromosome number is 2n = 32.
leaves
Adult plants usually have six to 13 leaves . The leaves are arranged in a spiral, their blades are subdivided into pinnate. The leaf sheaths form a striking crown shaft. The petiole is very short. At the top (adaxial) it has a groove, the bottom is rounded, both sides are densely hairy. The rachis is initially flat adaxially, then furrowed towards the tip. The bottom is rounded. It is also densely hairy.
The leaflets are lanceolate, simply folded, narrowed towards the tip, then truncated or slightly pointed. The leaf margin is serrated. There are reddish brown to pale scales on both surfaces, more dense on the underside and along the veins. The central rib stands out clearly, the marginal ribs are large, transverse vascular bundles are not recognizable.
Inflorescences
The inflorescences are individually under the leaves (infrafoliar). They are stiff and usually several are grouped below the crown shaft. They stand horizontally when they bloom and hang when they ripen. In the lower area they are threefold, higher up less strongly. All branches are densely hairy and flaky over time. The peduncle is short and stocky. The cover sheet is Roehrig, laterally two-keeled and slightly beaked. It has balding hair. The bract on the peduncle resembles the cover sheet, but is not keeled. The inflorescence axis is longer than the stalk and has very short, rounded bracts, in whose axils the side branches and rachillae sit. These, the flower-bearing axes, are rather short, sometimes zigzag-shaped, and have short, rounded bracts in which the large flowers stand in triads.
blossoms
The male flowers are slightly asymmetrical. The three sepals are greenish, not fused, imbricated and keeled towards the base. The three petals are not fused, valvate , oval and glabrous or densely covered with small, membranous scales. There are numerous stamens , mostly around 100 to 150. The outer filaments are easily fused with the petals. The filaments are creamy-white, short, awl-shaped and upright in the bud, not curved. The anthers are dorsifix, that is, the filaments attach to their back. The connective is tannic . The rudiment of the pistil is bottle-shaped, with the neck as long as the stamens. The pollen is ellipsoidal and asymmetrical. The germ opening is a distal sulcus . The longest axis measures 46 to 66 microns.
The female flowers are egg-shaped, pale green and smaller than the male when flowering. The three sepals are not fused, imbricat, rounded and sometimes covered with small hairs. The three petals are also not fused, broadly imbricated with short, thick valvate tips. They are sometimes densely covered with scales. They firmly encompass the gynoeceum themselves for anthesis . There are three staminodes , which are roughly combined into a low half-cup. The gynoeceum is egg-shaped, single-fan and has a single ovule . A stylus is not differentiated. The ovule hangs in the seed compartment and is pentagonal.
It is not known whether male or female flowers produce nectar . Related palms with similar flower structures are pollinated by bees and other hymenoptera .
Fruits and seeds
The fruit is egg-shaped, up to 6 cm long and dry, clearly furrowed and angular. When ripe it is orange to red. The inflorescence remains on the fruit as a large cup, the remnants of the stigma are somewhat eccentric. The exocarp is provided with short fiber bundles and brachysklereids . The mesocarp is orange, fleshy and contains tannic cells and vascular bundles without fiber sheaths. The endocarp has a large keel and is deeply furrowed. Between the furrows are three lateral and two ventral ridges. The wall is hard and thick. The semen is five-lobed, corresponding to the endocarp. The scar (hilum) is round and apical, the raphen branches are thin. The endosperm is homogeneous with a shallow edge furrow or it is deeply furrowed.
The manner in which the fruit spreads is unknown. In any case, the fruits show adaptations to the spread by animals ( zoochory ). Due to their size, however, most fruit-eating birds can be excluded. Fallen fruits are said to be eaten by cassowaries .
Distribution 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 rainforest along rivers, in the highlands on mountain ridges. Both species are also cultivated around villages. Ptychococcus lepidotus is widely grown in cemeteries. Some locations can also be traced back to naturalization, so that today the natural range can no longer be distinguished from the human-made range.
Systematics
The genus Ptychococcus Becc. is placed within the family Arecaceae in the subfamily Arecoideae , Tribus Areceae , Subtribus Ptychospermatinae .
Nine species have been described, Scott Zona only recognized two species in his 2005 genus revision. It was also followed by the World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew:
- Ptychococcus lepidotus H.E. Moore : The home is Papua New Guinea.
- Ptychococcus paradoxus (Scheff.) Becc. : The home is Papua Asia.
use
The hard wood is processed into hunting bows and spears. It is also used as lumber.
supporting 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.
Individual evidence
- ↑ Rafaël Govaerts (Ed.): Ptychococcus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 13, 2009.
Web links
- Ptychococcus on the homepage of the Fairchild Tropical Botanic Garden