Odonellia
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Odonellia are a plant genus of the family of wind plants (Convolvulaceae). It includes two types of American origin.
description
Vegetative characteristics
Odonellia are vigorous, herbaceous climbing plants . Stems , leaves , bracts , flower stalks , sepals and the folds of the petals are hairy sparsely or densely overlapping. The trichomes are long, rust-brown to pale yellow-red and unbranched.
The leaves are alternate. They are stalked, their leaf blades are broadly ovate or ovate with a prickly and pointed or pointed tip, the base is heart-shaped or cut off.
Inflorescences and flowers
The inflorescences are head-shaped cymes . They stand in the armpits and consist of a multitude of flowers . The inflorescence stalks are usually as long as the leaves or can be even longer, the flower stalks are very short. In an inflorescence there is a large number of sepal-like bracts that are as long or slightly longer than the sepals themselves. Their outside is densely hairy, the inside is hairless.
The five sepals are arranged like a roof in the bud (quincunicale bud cover). They are unevenly long and hairy similar to the bracts. The white to lavender-colored and bell-shaped, funnel-shaped and not lobed crown consists of five fused petals that have an inwardly folded, flapped (indupikat-valvate) bud cover. The central axis of the petals is densely hairy.
The five stamens are almost the same length and do not protrude beyond the crown. The stamens start near the base of the crown, the part that has grown together with the crown is covered with glandular hair. The anthers are turned inwards and slightly bent after opening. The pollen grains usually have six, rarely up to eight germ folds , all of which are equatorial. The stylus protrudes over the anthers, the two scar lobes are almost spherical and touch each other. The ovary is upper constant, zweikammerig and forms two in opposite direction (anatrope) ovules per chamber.
Fruits and seeds
The fruits are capsules that are enclosed by the constant bracts and sepals. Each fruit contains four hairless, smooth seeds in which the embryo is surrounded by persistent endosperm .
Occurrence and locations
The kinds of the genera occur in Mexico , Central America and South America .
Systematics
The genus includes two types:
- Odonellia eriocephala (Moric.) KR Robertson : Your home is Brazil.
- Odonellia hirtiflora (Mart. & Gal.) KR Robertson : It occurs from Mexico to tropical South America.
Type species is Odonellia hirtiflora .
Within the bindweed family, the genus is classified into the Aniseieae tribe according to molecular biological knowledge . In addition to the genus Odonellia , the genera Aniseia , Iseia and Tetralocularia also belong to this tribe.
Botanical history
Both species of the genus Odonellia were first described as belonging to the morning glory ( Ipomoea ) , Moïse Étienne Moricand described Ipomoea eriocephala in 1838 and Martin Martens and Henri Guillaume Galeotti described Ipomoea hirtiflora in 1845 . Both species were later assigned to the genus Jacquemontia , however, Kenneth R. Robertson found in 1971 in his studies of the species of the genus that some species are to be regarded as not belonging to the genus. Then he published the first description of the genus Odonellia in 1982 with the species Odonellia hirtiflora and Odonellia eriocephala . According to Robertson, the species of the genus Jacquemontia differ in their hairiness, the shape of the stigmas, the texture of the seeds and the shape of the pollen grains. Robertson assumed that the species should be placed close to the genus Aniseia , which was confirmed by molecular biological studies. The generic name honors Carlos Alberto O'Donell (1912–1954) for his extensive work on the South American representatives of the winch family.
swell
Individual evidence
- ↑ a b c Rafaël Govaerts (Ed.): Odonellia. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved February 11, 2015.
- ^ Saša Stefanović, Daniel Austin and Robert Olmstead: Classification of Convolvulaceae: A Phylogenetic Approach. In: Systematic Botany , Volume 28, Number 4, 2003. Pages 791-806. doi : 10.1043 / 02-45.1 (currently unavailable) ( online )
literature
- Kenneth R. Robertson: Odonellia, a New Genus of Convolvulaceae from Tropical America . In: Brittonia , Volume 34, Number 4, Oct./Dec. 1982. pp. 417-423