Ceratolobus
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Ceratolobus is a Southeast Asian, climbing palm genus .
features
The representatives are slender, multi-stemmed, climbing rattan palms. They are armed, blooming several times and dioeciously separate sexes ( diocesan ). The trunk becomes bald over time. It has long internodes and conspicuous leaf scars. A white mucus sometimes comes out of cuts.
The number of chromosomes is 2n = 26.
leaves
The leaves are pinnate. They carry a tendril (cirrhus) on adult, climbing shoot axes . The leaf sheath is tubular and covered with thorns or small spines. These are often in whorls . The vagina is often very hairy. There is a knee, but it is sometimes quite weak. The Ochrea is inconspicuous. The petiole may be missing. When present, it is flat on the top, rounded and reinforced on the underside. The tendril and the distal part of the rachis are decorated on the underside with regularly arranged hook thorns. There are relatively few leaflets. These are linear to lanceolate and entire, or rhombic and frayed. They stand regularly or in groups. When budding, the leaves have a pink tinge.
Inflorescences
The inflorescences are axillary, but are fused with the internode and the leaf sheath of the following leaf. They are sessile and erect, or pendulous on a long, slender peduncle . The entire inflorescence is significantly shorter than the leaves.
A male inflorescence has three orders of axes, a female two. The cover sheet is persistent, membranous to almost woody, flattened tubular with lateral wings and a terminal beak. The cover sheet completely encloses the inflorescence and opens into the anthesis with two side slits on the beak. This is the only access to flowers during flowering and the early fruiting stages. The cover sheet is unreinforced or reinforced with scattered thorns. It is often provided with an indument . When the fruit ripens, the cover sheet often tears open lengthways, and less often it falls off. Female and male inflorescences cannot be distinguished without opening the cover sheet.
There are no bracts on the peduncle . The bracts on the inflorescence axis are inconspicuous, tubular and, like the cover sheet in the axilla, have a first-order lateral axis.
blossoms
The male flowers are individually in an approximately two-line arrangement (subdistich) rather apart from each other on the axes. Each possesses a membranous triangular support sheet and a zweikielige Vorblatt -Brakteole. The calyx is tubular with three short, triangular lobes. The three petals are boat-shaped, valvate and briefly fused at the base. The six stamens attach to the base of the crown. Their filaments are short and fleshy, the anthers are linear and latrors. The rudiment of the stamp is three-lobed and very small. The pollen is ellipsoidal and bi-symmetrical. The germ openings are equatorial disulcat.
The female flowers stand together with a sterile male flower and two double-sided bracteole bracts in a cup formed by the bract . The sterile male flower resembles a fertile one, but has empty anthers and is stalked. The female flowers are larger than the male. The calyx is tubular with three short, triangular lobes. The crown is divided into three valvate, triangular lobes. The six staminodes are epipetal. The gynoeceum is incompletely triple with three ovules. It is spherical or ellipsoidal in shape, covered with scales, and bears three scars that are fleshy and bent back, standing on a short stylus . The ovule is basal and anatropic.
Fruits and seeds
The fruit is single-seeded, spherical to ellipsoidal and has scars at the top. The exocarp is covered with vertical rows of scales pointing downwards. The mesocarp is thin and papery to maturity. An endocarp is not developed. The seed is attached at the base, it is spherical to ellipsoidal. It has a thin or thick, sour or sweet tasting sarcotesta . The endosperm is homogeneous or furrowed.
Distribution and locations
The genus occurs in the perhumid areas of the Sunda Islands : on the Malay Peninsula, Sumatra , Borneo and Java . The species grow here in the lowland and hill rainforests up to 1000 m above sea level. They are mostly limited to the wing fruit forest, but Ceratolobus subangulatus is also found in the heather forests of Sarawak .
Systematics
The genus Ceratolobus is placed within the family Arecaceae in the subfamily Calamoideae , Tribus Calameae and Subtribus Calaminae . Within the subtribe it forms a monophyletic clade with Daemonorops and Pogonotium .
The genus includes six species. But today they are placed in the genus Calamus :
- Ceratolobus concolor flower : The home is Sumatra and Borneo.
- Ceratolobus discolor Becc. : The homeland is western Sumatra and Borneo.
- Ceratolobus glaucescens flower : The home is western Java.
- Ceratolobus kingianus Becc. & Hook.f. : The home is Malaysia.
- Ceratolobus pseudoconcolor J.Dransf. : The homeland is Sumatra and Java.
- Ceratolobus subangulatus (Miq.) Becc. : The home is Thailand to Malesia.
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. 204f.
Individual evidence
- ↑ Rafaël Govaerts (ed.): Ceratolobus. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 14, 2020.
Web links
- Ceratolobus on the homepage of the Fairchild Tropical Botanic Garden