Retispatha dumetosa
| Retispatha dumetosa | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Retispatha | ||||||||||||
| J.Dransf. | ||||||||||||
| Scientific name of the species | ||||||||||||
| Retispatha dumetosa | ||||||||||||
| J.Dransf. |
Retispatha dumetosa is a palm species endemic to Borneo . It is the only species in the genus Retispatha . The leaf sheaths , petioles and the rachis are densely reinforced.
features
Retispatha dumetosa is an upright or short climbing palm. It is reinforced, flourishes several times and has two separate sexes ( diocesan ). The trunk becomes bald over time, has noticeable scars on the nodes, and has rather short internodes . In the lower part of the trunk there are short, bulb-like shoots. Numerous adventitious roots attach to the lower node .
The number of chromosomes is not known.
leaves
The leaves have no tendrils and are pinnate. The leaf sheath is tubular, densely covered with slender spines that stand in whorls or partial whorls . They are also densely hairy. An ochrea is missing as well as a knee. The petiole is clearly developed and also densely reinforced. The rachis is studded with backward-pointing thorns that stand in groups of up to five. The leaflets are numerous and regularly arranged. They are once folded, linear and studded with bristles on the edges and main nerves.
Inflorescences
The inflorescences are in the leaf axils, but are fused with the internode and the leaf sheath of the following leaf. They are initially upright, later drooping. Male and female inflorescences are similar, but the male branches are up to three times, the female only single, rarely double. The cover sheet is large, tubular in the lower half, then torn. It is densely covered with black spines that stand in partial whorls. Bracts on the peduncle are missing. The bracts on the inflorescence axis resemble the previous leaf. The side axes of the first order hang down at the flowering time and carry imbricate, unreinforced bracts in two rows, the lower two thirds of which are tubular. They have a triangular edge, which consists of dense, criss-cross fibers, and which includes a kitten-like , contracted branching system in the male inflorescences . Each lateral axis of the second order stands in the armpit of a triangular, membranous, tubular bract with ciliate at the edge. The lateral axes of the third order, the rachillae, have membranous, ciliate tubular bracts, each bearing a double-sided, ciliate, tubular bractole and a single male flower .
In the female inflorescences, the flower-bearing axes, the rachillae are usually on the main axis, rarely also on a sometimes existing basal side branch. The bracts of the rachillae are two-lined (distich), are imbricat and similarly reticulate as on the male inflorescences. The rachillae are mostly covered by the bracts and have up to 20 distiche, tubular and ciliate bracts, each of which has a double-keeled cover leaf, a tubular bractole and a female flower.
blossoms
The male flowers are very small and symmetrical. The calyx is tubular with three triangular lobes, the tips of which are hairy. The crown is around twice as long as the calyx in the bud. It is tubular only at the base; the three lobes are striped and valvated . The receptacle elongates when it blooms, so that the crown appears tubular in the lower third. The six stamens are free from the crown in the bud. The filaments are connected to one another at the sides. The anthers are elongated to oval, dorsifix near the base and latrors. The rudiment of the stamp consists of three parts and is very small. The pollen is ellipsoidal and bisymmetrical. The germ openings are equatorial and are disulcat.
The female flowers are much larger than the male. The calyx is tubular with three short, triangular lobes. It tears open after flowering. The crown is tubular and slightly shorter than the cup. It has three short, valvate lobes and also tears. The filaments of the six staminodes form a short tube, the empty anthers are flat. The gynoeceum is incompletely triple with three ovules . It is egg-shaped, scaled and has three scars that are conspicuous and fleshy and stand on a non-scaled stylus . The ovule stands basal and is anatropic.
fruit
The fruit is solitary and partially covered by the reticulate bracts. It is egg-shaped to slightly pear-shaped. It is beaked with an apical scar remnant. The exocarp is covered with vertical rows of scales pointing downwards. The mesocarp is thin and an endocarp is not differentiated. The seed is basal and has a thin, sweet sarcotesta .
Distribution and locations
Retispatha dumetosa is a species of flora endemic to Borneo. It is only known from scattered locations across the island. It forms thickets on slopes and valley floors in dipterocarp forests. It is absent in mountain and heather forests. While it is widespread, it is still rare.
Systematics
The genus Retispatha J.Dransf. is placed within the family Arecaceae in the subfamily Calamoideae , Tribus Calameae and Subtribus Calaminae.
In the World Checklist of Selected Plant Families of the Royal Botanic Gardens (Kew) , only the species Retispatha dumetosa J.Dransf. accepted. In 2018, however, the species was assigned to the genus Calamus .
The name is composed of the Latin word rete for net and the Greek spáthē for bract and refers to the net-shaped bracts in the inflorescences.
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. 197f.
Individual evidence
- ↑ Rafaël Govaerts (ed.): Rethispatha. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved August 2, 2018.
Web links
- Retispatha on the homepage of the Fairchild Tropical Botanic Garden