Sclerosperma

Sclerosperma is a native to the rainforests of West Africa palm genus. She is the only member of the tribe Sclerospermeae. The representatives have an unusual for palm inflorescence: he is erect, unbranched and bears forced standing flowers.

• 4.1 Notes and references

Features

The representatives are usually stemless and grow in clumps. They often form thickets. They are unarmed, monoecious and repeatedly flowering. The trunk is, if any, creeping or erect, rather thick and densely covered with annular leaf scars.

The chromosome number is unknown.

The leaves are reduplicat ( cross section of the pinnules Λ -shaped), two-piece ( bifid ) or pinnate, and very large. For young plants, the leaves are deeply bifid. The leaf sheath is rather short and rips open opposite the petiole, the margins are fibrous. The petiole is long, slender, furrowed on the upper side, rounded at the bottom. The leaflets, when present, consist of several very narrow folds. The middle ribs are formed clearly. The leaf blade is dunk at the top, fitted at the bottom with a dense amorphous white Behaarungen and to the nerves with small scales. The leaflets are pulled out at the end ( prämors ). The leaf margin is finely serrated.

Inflorescences

The inflorescences are between the sheets ( interfoliar ) and are hidden among the leaf bases, sometimes additionally obscured by deposits. They are upright, stocky and spike -shaped. The peduncle is very short, hairy and dense elliptical in cross section. The cover page is rather short, strong zweikielig and later zerfasernd. The bract on peduncle is longer than the previous sheet, Roehrig, forming a dense fiber network around the flowers. It opens distally and are so inflorescence partly free. Two other, incomplete, pointed bracts protrude laterally just below the blooms. The inflorescence axis is longer than the peduncle, but still short, stocky and wearing a few ( around 12 ) triads flowers at the base and numerous rows of male flowers distally. Each triad is supported by a flat, pointed, fibrous bract, the male of small acute bracts. The flowers - Brakteolen are present in the triads and flat, rounded and partly overgrown.

Flowers

The male flowers of the triads are stalked and asymmetric, the distal flowers are sessile and symmetrical. All the male flowers have three free sepals, which are basal imbricat. They are long, verschmälernt upward apically truncate or with eggs short central peak. The three petals are free, valvat with flattened tips. There are 60 to 100 stamens. Their filaments are very short, rather triangular, the anthers are oblong, basifix, open latrörs itself. The connective is clearly developed. A stamp rudiment is missing. The pollen is symmetrical and triangular in polar view of flattened. He is heteropolar: on the distal side are three operculate subapical germ pore.

The female flowers are larger than the male and broadly ovate. The three sepals are fused together into a tricuspid, bare cup, or the edges of two sepals are free and imbricat. The three petals are asymmetrical, wide imbricat with thick valvaten tips. There are six very small staminodes, but they can also missing. The gynoecium is ovoid, unicompartmental occupied by a seed plant with thin, brown scales. The scar is large, cap-shaped and triangular. The ovule is campylotrop more or less coherent and probable.

Fruit and seeds

The fruits are globose to obovate. Apical they are pushed around the short beak with the residual scars something. The color of the fruit ripening is purple to black. The exocarp is thin, the mesocarp is thin, parenchymatous with (possibly) silicate inclusions. The endocarp is bony, thick, irregularly outside provided with shallow pits. The seed is globose to obovate, slightly rough. The hilum is elongated, the endosperm is homogeneous, the embryo is located basally.

Dissemination and locations

The genus occurs in the perhumiden tropical rainforests of the equatorial West Africa, the area around the Gulf of Guinea. The representatives grow mainly in low-lying, damp, marshy areas.

System

The genus Sclerosperma is placed in the subfamily within the family Arecaceae Arecoideae alone forms the tribe Sclerospermeae. The monophyly has not been studied. The Sclerospermeae form a clade together with the Oranieae and Podococceae.

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

• Sclerosperma mannii
• Sclerosperma profizianum
• Sclerosperma walkeri

Sclerosperma was first described by G. Mann and Hermann Wendland 1864 type species is Sclerosperma mannii. The genus name is derived from the ancient Greek words for hard and seeds, a reference to the hard endosperm.

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. 389-391.