Calyptronoma

Calyptronoma is a native to the islands of the Greater Antilles palm genus.

• 4.1 Notes and references

Features

The representatives are large, non-reinforced palms, while most other species of the tribe Geonomateae are plants of the undergrowth of forests. The palm trees are monoecious getrenntgeschlechtig ( monoecious ) and repeatedly flowering. They form a single stem that reaches a diameter of 15 to 30 cm. The strain carries conspicuous leaf scars and perpendicular cracks, the color is gray-brown.

The chromosome number is 2n = 28

The leaves are in schraubiger arrangement and are pinnate. They are vertical horizontal to approximately. The leaf bases are not resistant. A Kronschaft is not formed. The leaf bases are on the edge of fibrous, the petiole is short (less than 50 cm long). The leaf blade is divided evenly into similar-sized leaf segments. The segments are linear to lanceolate with a single main vein and several secondary veins. The larger veins carry on the underside of leaves shed. The ends of the segments are not articulated and pointed. The segments are folded reduplicat.

In all species, there are populations whose leaves, bracts or sepals are reddish-brown to purple.

Inflorescences

The inflorescences appear singly in the axils of leaves leaf. They are three times, very rarely branched four times. A cover sheet is available, as a single, lederiges bract on peduncle, which sits at the base of the stem. The bract is included in the lower part of the cover page, in the upper part but free.

The axes of the inflorescence are covered with spider-web- hair when they are young, then aged bald. The flower-bearing axes ( Rachillae ) are in the lower part of the inflorescence axis in bundles, then individually at the top. The lower Rachillae are longer than the upper. The flowers sit in pits. Each hole is surrounded by a high sheet whose shape is species specific.

Flowers

The flowers are in triads, with one female flower flanked by two male.

The male flowers have three free sepals, which have a dark pigmented Kiel. The dorsal sepal is smaller than the other two. There are three petals. In Calyptronoma occidentalis and Calyptronoma plumeriana they are partially fused, the free tip are valvat and open at flowering. In Calyptronoma rivalis they are fully grown, and fall off as a cap using a round Abszissionszone. This is the only known example within the palms for such caps in male flowers. The six stamens are fused into a fleshy, funnel-shaped tube, sit at the top short free filaments. The androecium project beyond the perianth, to flower, the filaments are bent back. The anthers are pfleilförmig, dorsifix near the base. The stamp rudiment is very small.

The pollen grains are monosulcat, rarely trichotomosulcat. Your outline is elliptical. The surface of the tectum is structured species specific.

The female flowers have very similar to those of male flowers sepals. The petals are fused over the whole length and open over a round Abszissionszone that releases a cap. The fused staminodes form a tube with six small lobes. At the height of the distal zone is inflated and extends beyond the perianth addition. In older flowers then lacks this distal region and only the tube is still present. The gynoecium consists of three carpels and has a long, slender pen with a three-lobed stigma. The ovules are anatrop. One of the three subjects is smaller than the other two and contains a small, mostly sterile ovule.

Fruit and seeds

The fruit is a drupe, with exocarp, mesocarp and endocarp are clearly developed. The fruit is obovate and dorsiventrally somewhat compressed. The scars radicals basal. The exocarp is smooth and turns green during the maturation of red to purple on black. The mesocarp is juicy and meaty, interspersed with fibers. The endocarp is tender. In Calytronoma occidentalis and Calyptronoma plumeriana it is like a net and not fused with the seed in Calyptronoma rivalis it is firmly attached to the seed and only removed like a net.

The seeds are spherical to ellipsoidal and how the fruit is pressed dorsiventrally something. The seed coat is smooth and brown black, it has a straight raphe and a small, basal hilum ( scar ). The embryo sits basal to suprabasal and is very small. The endosperm is homogeneous.

Dissemination and locations

The genus is found only in the Greater Antilles, where the representatives in marshes, near the sea, river banks and in the mountains grow in moist locations.

System

Calyptronoma is classified within the palm family ( Arecaceae ) in the subfamily Arecoideae, Tribe Geonomateae. The genus is closely related to Calyptrogyne. Whether the species is monophyletic or paraphyletic with respect to Calyptrogyne, is not yet finally resolved.

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

• Calyptronoma occidentalis
• Calyptronoma plumeriana
• Calyptronoma rivalis

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. 478-480.
• Scott Zona: A revision of Calyptronoma ( Arecaceae ). Principes, Volume 39, 1995, pp. 140-151.