Laccosperma
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| Scientific name | ||||||||||||
| Laccosperma | ||||||||||||
| ( G. Mann & H. Wendl. ) Drude |
Laccosperma is a climbing palm genus native to tropical Africa. It is one of the few palm species in which the trunk also branches above ground.
features
The representatives are multi-stemmed, high-climbing rattan palms with pinnate leaves. They only bloom once in a lifetime ( hapaxanth ) and are hermaphroditic. You are armed. The trunk sometimes branches above the surface of the earth, a rarity in palm trees. The internodes are long. The trunk cross-section is circular. Side shoots appear axillary.
The number of chromosomes is unknown.
leaves
The leaves are pinnate with a cirrhus . The leaf sheath is always Roehrig, it is scattered with spines and hairy. The ochrea, the part of the leaf sheath below the base of the petiole, is clearly present, often slightly inflated and populated with ants . The ochrea can also be reinforced. The petiole is present and also reinforced. The rhachis is also reinforced, as is the cirrhus. Here the spines are bent back. The cirrhus also bears pairs of acanthophylls . There are few to numerous leaflets. These are folded one to four times, with entire margins, straight to sigmoidal. They stand evenly or unevenly along the rachis. They are often densely covered with short spines on the leaf margins.
Inflorescences
The inflorescences are formed all at once in the axils of the most distal leaves, which are often reduced. An inflorescence is simply branched. The inflorescence stalk is enclosed in the leaf sheath ; it protrudes from the vaginal opening or breaks through the vagina. The stalk is not fused with the internode . The cover sheet (Prophyll) is roehrig, two-keeled and enclosed in the leaf sheath. There are one to three bracts on the peduncle. The inflorescence axis is longer than the stalk. The bracts on the axis stand in two lines (distich), are tubular with a triangular lobe, unreinforced and hairy. A hanging or protruding rachilla (flower-bearing axis) rises from each bract. The cover leaf of the Rachilla is tubular and two-keeled and enclosed in the bract . The rachilla bracts are distich, are tubular with triangular end lobes with sometimes a ciliate edge. In each bract there is a group of flowers.
blossoms
The flowers are usually in pairs, rarely in triads, sometimes only individually. The flower groups have a tubular, two- keeled cover leaf and - depending on the number of flowers - 0, 1 or 2 bracteoles . The calyx is stem-like at the base, often bent at right angles. At the end it is split into three triangular lobes. The crown is also tubular at the base and divided into three elongated, narrow, triangular lobes at the top. The six stamens start at the base of the crown, the stamens are separated from each other, swollen and hardly narrowed at the connective. The anthers are attached in the middle (medifix), long and latrors. The gynoeceum is triple with three ovules . The ovary is covered with scales. The stylus is long, triangular, the stigma is very small, pyramidal. The ovules are basal and anatropic .
The pollen is ellipsoidal and bisymmetrical. The germ opening is a distal sulcus . The longest axis measures 37 to 75 microns.
Fruits and seeds
The fruit is solitary, the remnant of the stylus sits at its tip. The perianth leaves are preserved. The exocarp is covered with vertical rows of scales. The mesocarp is fleshy and sweet when ripe. The endocarp is not differentiated.
The seed is egg-shaped and laterally flattened, or rounded and deeply curved, with a shallow to very deep lateral pit. The seed coat is sometimes fleshy. The endosperm is homogeneous. The embryo sits on the side, opposite the pit.
Distribution and locations
The representatives occur in the humid rainforests of West Africa and the Congo Basin. They are most commonly found on swampy ground.
Systematics
The genus Laccosperma (G. Mann & H. Wendl.) Drude is placed within the family Arecaceae in the subfamily Calamoideae , Tribus Lepidocaryeae , Subtribus Ancistrophyllinae . It is the sister group of Eremospatha (G. Mann & H. Wendl.) H. Wendl. The genus is monophyletic .
The Royal Botanic Gardens, Kew's World Checklist of Selected Plant Families recognizes the following species:
- Laccosperma acutiflorum (Becc.) J.Dransf. : It occurs in tropical West Africa and in west-central tropical Africa.
- Laccosperma cristalensis Couvreur & Niang. : The species first described in 2016 occurs in Gabon.
- Laccosperma korupense Sunderl. : It occurs from Cameroon to the Democratic Republic of the Congo.
- Laccosperma laeve (G. Mann & H. Wendl.) Kuntze : It occurs in western and western-central tropical Africa.
- Laccosperma opacum Drude : It occurs in western and western-central tropical Africa.
- Laccosperma robustum (Burret) J.Dransf. : It occurs from Nigeria to west-central tropical Africa.
- Laccosperma secundiflorum (P.Beauv.) Kuntze : It occurs in western and western-central tropical Africa.
The name is made up of the words laccos = hole, pit and sperma = seed and refers to the deep pit in the seed of some species.
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. 152-154.
Individual evidence
- ↑ a b c d e f g h Rafaël Govaerts (Ed.): Laccosperma. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved July 31, 2018.
Web links
- Laccosperma on the homepage of the Fairchild Tropical Botanic Garden