Hydnora
| Hydnora | ||||||||||||
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Blossom of Hydnora africana |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Hydnora | ||||||||||||
| Thunb. |
Hydnora is a genus from the family of hydnoraceae within the order of the pepper-like (Piperales). The genus includes seven species that live as root parasites and are only found in Africa , Madagascar and southern Arabia .
description
All species are root parasites without chlorophyll and live completely underground with the exception of the flower and fruit (in Hydnora triceps , however, the flower and fruit are also formed underground). The roots are up to 10 centimeters thick, cylindrical to flattened, firm strands that are only weakly branched and spread out laterally from the hosts. They are the only covers that are completely leafless.
The length of the inflorescence is determined by the depth at which the root lies; the peduncle measures between 4 and 9 centimeters. Except for the Madagascan Hydnora esculenta , all species are hermaphroditic. The individual flowers, measuring 5 to 25 centimeters in diameter, are three to five-fold ( Hydnora ). The 6 to 8 centimeter long flower lobes either lie wide open on the ground or are not bent back and only open by separating the individual lobes from one another. In some species, slightly thickened, whitish outgrowths reminiscent of maggots can be found on the edge of the lobes. The flowers give off a foul-smelling fragrance.
The ovaries are below, with numerous, "folded" placentas , the scars are grooved. The stamens are fused, the pollen is monocolpat, so it has only one opening for germs. As far as is known, the plants are pollinated by beetles, ants or flies, the fruit is fleshy. In the white pulp there are numerous small seeds that are eaten by animals and distributed through their excretions.
The plants are host-specific and they parasitize either on milkweed species ( Euphorbia ) or acacias ( Acacia ).
distribution
Hydnora is native to southern and eastern Africa including Madagascar and sporadically radiates to the Arabian Peninsula (Yemen, Saudi Arabia, Oman). Only Hydnora abyssinica and Hydnora africana are more widespread, the possibly already extinct Hydnora esculenta is endemic in Madagascar, Hydnora triceps in the border region of Namibia and South Africa and the Hydnora sinandevu, which was first described in 2002, in the coastal borderland of Kenya and Tanzania.
The species colonize semi-deserts, where their distribution is linked to the occurrence of the hosts.
Systematics
The following types are known so far:
- Hydnora abyssinica A.Br. (Syn .: Hydnora johannis Becc. ): It occurs from Eritrea to southern Africa and on the Arabian Peninsula.
- Hydnora africana Thunb. (Syn .: Hydnora longicollis Welw. ): It occurs from southwestern Angola to South Africa.
- Hydnora esculenta Jum. & H.Perrier : Your home is southern and southwestern Madagascar.
- Hydnora longicollis (Welw.) Bolin : It occurs in Angola.
- Hydnora sinandevu Beentje & Q.Luke : The species that was first described in 2002 occurs in Kenya and northeastern Tanzania.
- Hydnora triceps Drège & E. Mey. : The species occurs only in the Western Cape.
- Hydnora visseri Bolin, E. Maass & Musselman : The species occurs from Namibia to the Western Cape.
literature
The information in this article was obtained from the following sources:
- Lytton John Musselman: The Genus Hydnora (Hydnoraceae) , In: JK Ransom, LJ Musselman, AD Worsham and C. Parker (Eds.): Proceedings of the 5th International Symposium of Parasitic Weeds. The International Maize and Wheat Improvement Center (CIMMYT), Nairobi 1991, ISBN 978-968-6127-58-4 , pp. 247-25, ( online ).
- Kushan U. Tennakoon, Jay F. Bolin, Lytton John Musselman: "Pilot Roots" of Hydnora triceps and H. africana (Hydnoraceae) are stems. Poster, Proceedings of the Botanical Society of America (Austin, Texas), August, 2005: 43 online (JPG) .
- Erika Maass & Lytton John Musselman: Hydnora triceps (Hydnoraceae) - First record in Namibia and first description of fruits. In: Dinteria - Contributions to the Flora and Vegetation of Namibia. 29/2004, online . (PDF; 1.29 MB), from nbri.org.na, accessed on November 4, 2016.
Individual evidence
- ↑ Entry in the List of Targeted Plant Species, Subspecies, and Varieties in the Eastern Arc Mountains and Coastal Forests of Tanzania and Kenya (accessed July 5, 2007)
- ↑ a b c d e f Rafaël Govaerts (Ed.): Hydnora - data sheet at World Checklist of Selected Plant Families of the Board of Trustees of the Royal Botanic Gardens, Kew. Last accessed on April 17, 2015.
- ^ Hydnora longicollis (Welw.) Bolin at Tropicos.org. Missouri Botanical Garden, St. Louis
