Striga gesnerioides
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Striga gesnerioides in a field in Tambaga , Burkina Faso |
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| Striga gesnerioides | ||||||||||||
| ( Willd. ) Vatke |
Striga gesnerioides is a plant type from the genus Striga in the family of broomrape plants (Orobanchaceae).
description
Striga gesnerioides is a 12 to 30 cm high, parasitic , annual or occasionally perennial plant . It grows straight or branched at the base, is usually succulent, and dries brown or black. It is sparsely to densely stiff-haired or fine-haired. The stem is round or indistinctly square. The leaves have a size of 4 to 10 × 1 to 3 mm, are lanceolate, with entire margins and are opposite or almost opposite. They are scale-like, close-fitting, are shorter than the internodes and have an indistinct vein.
The flowers are opposite or almost opposite in a simple spike-like inflorescence , which can be longer or shorter than the vegetative shoot. The flowers are each accompanied by two bracts , these are 2.5 to 6 × 2 to 3 mm in size, lanceolate and longer or shorter than the calyx .
The calyx is five-ribbed and 4 to 9 mm long. The calyx tube has a length of 3 to 6 mm. It is occupied with five unequal or almost equal lobes, which are linear, triangular or lanceolate, have a length of 1 to 3 mm and are thus shorter than the corolla tube. The crown is creamy white, blue, pink or purple. The corolla-tube is 8 to 14 mm long, curved, expanded above the calyx and covered with very few glandular or non-glandular hairs. The lobes of the lower lip are 2 to 6 × 1.3 to 3 mm in size, they are inverted ovoid and protruding. The upper lip has a size of 1 to 2 × 2 to 2.5 mm, it is inconspicuously bilobed or notched and usually wider than it is long.
The number of chromosomes is 2n = 40.
Occurrence
Striga gesneroides is the most common species of the genus. Their distribution area in Africa extends to Arabia and Asia. It was introduced to Florida, but has so far not been a problem there.
In contrast to most other species of the genera, the species parasitizes exclusively on dicotyledons . Within the species, there are population groups with specific host ties that do not differ morphologically enough to be treated as separate species or subspecies. For the African distribution area, for example, a distinction is made between lines that parasitize on various butterflies ( Indigofera , Tephrosia , Vigna ), bindweed ( Ipomoea , Jacquemontia , Merremia ) as well as on tobacco ( Nicotiana ) and on tree-shaped spurge species ( Euphorbia ).
literature
- Kamal I. Mohamed, Lytton John Musselman and Charles R. Riches: The Genus Striga (Scrophulariaceae) in Africa . In: Annals of the Missouri Botanical Garden , Volume 88, Number 1, Winter 2001. Pages 60-103.
Individual evidence
- ^ Striga gesnerioides at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
- ↑ Kamal I. Mohamed, Lytton John Musselman and Charles R. Riches: The Genus Striga (Scrophulariaceae) in Africa . In: Annals of the Missouri Botanical Garden , Volume 88, Number 1, Winter 2001. Pages 60-103.
Web links
- Striga gesnerioides in U. Brunken, M. Schmidt, S. Dressler, T. Janssen, A. Thombiano & G. Zizka: West African plants - A Photo Guide. Senckenberg Research Institute, Frankfurt / Main 2008.