Calyptronoma
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Calyptronoma rivalis |
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| Calyptronoma | ||||||||||||
| Griseb. |
Calyptronoma is a genus of palm that is nativeto the islands of the Greater Antilles .
features
The representatives are large, unreinforced palm trees, while most of the other species of the tribe Geonomateae are plants of the undergrowth of the forests. The palms are single sexed ( monoecious ) and bloom several times. They form a single trunk that reaches a diameter of 15 to 30 cm. The trunk has striking leaf scars and vertical cracks, the color is gray-brown.
The chromosome number is 2n = 28.
leaves
The leaves are in a helical arrangement and are pinnate. They stand vertically to almost horizontally. The leaf bases are not stable. A crown shank is not formed. The leaf bases are fibrous on the edge, the petiole is short (less than 50 cm long). The leaf blade is evenly divided into leaf segments of similar size. The segments are linear to lanceolate with a single main artery and several secondary arteries. The larger veins have scales on the underside of the leaf. The ends of the segments are undivided and pointed. The segments are folded in duplicate.
In all species there are populations whose leaves, bracts or sepals are red-brown to purple-red in color.
Inflorescences
The inflorescences stand individually in the axils of a leaf. They are three-fold, very rarely four-fold. A cover sheet is present, as is a single, leathery bract on the inflorescence stalk that sits at the base of the stem. The bract is enclosed by the previous sheet in the lower part, but free in the upper part.
The axes of the inflorescence are covered with cobweb-like hairs when they are young, when they are old they are bare. The flower-bearing axes (rachillae) are in the lower part of the inflorescence axis in bundles, in the upper area then individually. The lower rachillae are longer than the upper ones. The flowers sit in pits. Each pit is enclosed by a bract, the shape of which is species-specific.
blossoms
The flowers are in triads, with a female flower flanked by two male ones.
The male flowers have three free sepals that have a dark pigmented keel. 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 tips are valvate and open during flowering. With Calyptronoma rivalis they are completely fused and fall off as a cap with the help of a round abscission zone. This is the only known example within the palms of such caps on male flowers. The six stamens are fused into a fleshy, funnel-shaped tube with short free filaments at the top. The androeceum protrudes beyond the flower envelope, the filaments are bent back towards the flower. The anthers are nurse-shaped, dorsifix near the base. The stamp rudiment is very small.
The pollen grains are monosulcat, rarely trichotomosulcat. Its outline is elliptical. The surface of the tectum has a species-specific structure.
The female flowers have sepals very similar to those of the male flowers. The petals are fused over the entire length and open over a round abscission zone that exposes a cap. The overgrown staminodes form a tube with six small lobes. The distal zone is inflated during flowering and extends beyond the flower envelope. In older flowers this distal area is missing and only the tube is still present. The gynoecium composed of fused carpels three and has a long, slender pen with a trilobal scar . The ovules are anatropic. One of the three compartments is smaller than the other two and contains a small, mostly sterile ovule.
Fruits and seeds
The fruit is a stone fruit , with the exocarp , mesocarp and endocarp clearly developed. The fruit is obovate and somewhat compressed dorsiventrally. The scar remains are basal. The exocarp is smooth and changes color from green to red to purple-black as it ripens. The mesocarp is juicy and fleshy, interspersed with fibers. The endocarp is tender. In Calytronoma occidentalis and Calyptronoma plumeriana it is reticulated and not fused with the seed, in Calyptronoma rivalis it is firmly connected to the seed and only remotely reticulated.
The seeds are spherical to ellipsoidal and, like the fruits, somewhat depressed dorsiventrally. The seed coat is smooth and brown-black, it has an unbranched raphe and a small, basal hilum (scar). The embryo sits basal to suprabasal and is very small. The endosperm is homogeneous.
Distribution and locations
The genus occurs only in the Greater Antilles, where the representatives grow in swamps, near the sea, on river banks and in the mountains on moist locations.
Systematics
Calyptronoma Griseb. is classified within the palm family (Arecaceae) in the subfamily Arecoideae , Tribus Geonomateae . The genus is closely related to Calyptrogyne . Whether the genus is monophyletic or paraphyletic in relation to calyptrogyny has not yet been definitively clarified.
In the World Checklist of Selected Plant Families of the Royal Botanic Gardens, Kew , the following types are recognized:
- Calyptronoma occidentalis (Sw.) HEMoore : The home is Cuba and Jamaica.
- Calyptronoma plumeriana (Mart.) Lourteig : The home is Cuba, the Dominican Republic and Haiti.
- Calyptronoma rivalis (OFCook) LHBailey : It is native to Hispaniola and Puerto Rico.
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. 478-480.
- Scott Zona: A Revision of Calyptronoma (Arecaceae) . Principes, Vol. 39, 1995, pp. 140-151.
Individual evidence
- ↑ Rafaël Govaerts (Ed.): Calyptronoma. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved February 19, 2011.
Web links
- Calyptronoma on the homepage of the Fairchild Tropical Botanic Garden