Dicranostyles
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Dicranostyles scandens (Herbarium specimen) |
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| Scientific name | ||||||||||||
| Dicranostyles | ||||||||||||
| Benth. |
Dicranostyles is a plant genus in the family of wind plants (Convolvulaceae). The 15 or so species are common in South America.
description
Vegetative characteristics
Dicranostyles are lianas whose shoot axes , which are over 30 m long, reach a diameter of over 15 cm and are smooth to slightly grooved.
The alternate leaves are arranged in a petiole and a leaf blade. The leaf stalks are runny. The simple leaf blades are membranous, sometimes almost leathery. The base of the blade is tapered, pointed or blunt, only occasionally rounded, heart-shaped or cut off. The spreader tips are pointed or rarely cut off. The leaf margin is entire. The leaf vein is loopy (brochidrodrom). The occasionally non-permanent hair ( indument ) is fluffy or upright fine. There are no stipules .
Inflorescences and flowers
The lateral inflorescences are mostly in more or less clear groups in the leaf axils or along the internodes . The inflorescences are traubig , traubig- thyrsenförmig , cylindrical-thyrsenförmig or thyrsenförmig constructed and applied, bifurcated trichomes hairy. The bracts are mostly ovate, persistent and finely haired, rarely hairless. The bracts are scale-shaped.
The hermaphrodite flowers are five-fold with a double flower envelope . There is a valvat-induplicate (folded inwardly folded) bud cover . The sepals overlap roof-like (quincuncial), the outer sepals are mostly egg-shaped and pointed towards the front, the inner ones are broadly egg-shaped to almost round and rounded towards the front. The areas of the sepals that are not covered by other parts of the flower are usually finely haired, the covered areas are mostly hairless. The crown is white or occasionally pink in color and very small with a length of only 5 mm (rarely up to 8 mm). The shape is almost wheel-shaped or funnel-shaped, in the first case the sepals are divided almost to the base, in the second case they grow together over half the length or more. The corolla lobes thus formed are elongated to elongated triangular. The tips are pointed to round, the edges are rolled up, bent inward, upright or bent back at flowering time. The outside of the crown is finely hairy, the inside is rarely hairy.
The stamens are on the same radius as the petals (epipetal) and either protrude between the corolla lobes or are bent inward and stand together at the end of the corolla tube. The stamens are thread-like or taper from a widened to flat triangular base. The base is free and can be covered with shaggy hair or is fused with the corolla tube and is then often covered with a longitudinal ring of glandular hair. The anthers are fixed on the back, elliptical-round, elongated, egg-shaped or triangular, their base is arrow-shaped. The flower base is cup-shaped and covered with five lobes that may produce nectar . The ovary is usually ovate to conical-ovoid, occasionally obovate. The styles are fused and only divided into two short branches or completely divided. The scars are bilobed, the scar lobes being flat, spherical, rounded, cylindrical or pear-shaped and free or close-fitting.
Fruits and seeds
The fruits are nut-like, elliptical to elliptical-cylindrical. They form a thick, leathery to woody pericarp . Due to the stunting of the ovules , they usually develop only one, rarely up to four seeds . These are hairless, ovate to elongated ovate, or triangular if there is more than one seed per fruit. The seed coat is soft and leathery, the endosperm is only slightly pronounced or completely absent. The cotyledons are thin, folded along the central axis and lengthways.
distribution
The species of the subgenus Dicranostyles come between the Venezuelan Sierra Imataca near the mouth of the Rio Orinoco to the Brazilian state Pará in the east, the Brazilian states of Rondônia and Acre , the Bolivian El Beni and the Peruvian regions Loreto and Amazonas in the southwest and up to to the south side of the coastal Andes in Venezuela.
The subgenus Kuhlmanniella (Barroso) DFAustin occurs mainly in a smaller area, which extends along the upper reaches of the Amazon in Brazil and Peru.
Systematics
Taxonomy
The genus Dicranostyles was established by George Bentham . The type species is Dicranostyles scandens Benth.
External system
Within the bindweed family, the genus is classified into the Maripeae tribe according to molecular biological knowledge . In addition to the genus Dicranostyles , the genera Maripa and Lysiostyles also belong to this tribe.
Internal system
The genus Dicranostyles includes 15 species, which are divided into two sub-genera.
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Individual evidence
- ^ Saša Stefanović, Daniel Austin, Robert Olmstead: Classification of Convolvulaceae: A Phylogenetic Approach. In: Systematic Botany , Volume 28, Number 4, 2003, pp. 791-806. (PDF; 318 kB)
- ↑ a b c d e f g h i j k l m n o Rafaël Govaerts (Ed.): Dicranostyles. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved November 30, 2017.
literature
- Daniel Austin: The American Erycibeae (Convolvulaceae): Maripa, Dicranostyles, and Lysiostyles. I. Systematics. In: Annals of the Missouri Botanical Garden , Volume 60, 1973, pp. 306-412. scanned at biodiversitylibrary.org .
