Abstract Detail

After the book - Progress in parasitic plant research since Kuijt's Biology of Parasitic Flowering Plants (1969)

Maass, Erika [2], Musselman, Lytton John [1], Boles, Sandra [1].

Hydnora - The Ingenious Genus.

The Hydnoraceae is a family of holoparasitic root parasites, poorly studied mainly because of their furtive nature. They spend most of their life beneath the soil. The only parts of the plants that develop above the soil surface are flowers. Hydnora triceps is the only known dicot with hypogeous flowering. The successful subterranean existence of Hydnora is made possible through a variety of adaptations, most of which are not yet fully understood. Three of the four currently recognized species occur in Namibia. Various aspects of the biology of these three species, ( H. africana, H. triceps and H.abyssinica) were studied over a period of four years. Based on field observations and DNA studies, a remarkable story about the natural history of Hydnora is beginning to unfold. While little is known about pollination strategies, studies on floral development strongly indicate that the flowers are dichogamous, especially in the case of H. africana and H. triceps. The opening in the center of the antheral ring that allows entrance to the female part of the flower constricts after pollen shedding, thereby preventing pollinators from reaching the stigma. This seems to be less pronounced in H.abyssinica where the antheral ring stays open. As is the case with other holoparasitic root parasites, dormancy mechanisms prevent seed germination in the absence of a host root. While no information exists on seed dispersal, field observations indicate that small mammals are involved. The way in which the parasitic seeds are brought into close contact with the roots of the host remains a mystery.

1 - Old Dominion University, Department of Biological Sciences, Norfolk, Virginia, 23529-0266, USA
2 - University of Namibia, Department of Biology, Private Bag 13301, Windhoek, , Namibia

Keywords:
holoparasite
Euphorbia
Floral biology
hypogeous flowering
seed germination.

Presentation Type: Symposium
Session: 16-4
Location: Ballroom 2 (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 2:45 PM
Abstract ID:533