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Natural History of the Strangest Plants in the World

Natural History of the Strangest Plants in the World . Hydnora africana, Karasburg District, Namibia. August 2003. Lytton John Musselman Old Dominion University. Features of the family Phylogeny of the family Taxonomy Floral biology Diaspore. Introducing the Hydnoraceae.

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Natural History of the Strangest Plants in the World

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  1. Natural History of the Strangest Plants in the World Hydnora africana, Karasburg District, Namibia August 2003

  2. Lytton John Musselman Old Dominion University

  3. Features of the familyPhylogeny of the familyTaxonomyFloral biologyDiaspore

  4. Introducing the Hydnoraceae

  5. Features of the Hydnoraceae • No leaves or scales (unique among angiosperms) • Subterranean holoparasites of semi-arid regions • Relatively host specific • Monocolpate pollen

  6. Habit ofHydnoraceae Succulent herbs Achlorophyllous Obligate parasites

  7. Systematic position of the Hydnoraceae has long been debated due to extreme morphologial reduction.

  8. Molecular data place Hydnoraceae with Aristolochiaceae “Palaeoherbs”

  9. Taxonomy

  10. Only two genera comprise the Hydnoraceae: Hydnora and Prosopanche.

  11. Hydnora-African • H. johannis(=H. abyssinica)-widespread across Africa. • H. africana-Restricted to southern Africa. • H. triceps-found only in a small area along the Orange River in South Africa/Namibia.

  12. Hydnora-African • H. esculenta-Madagascar, a poorly known species. • H. sinandevu-Kenya and Tanzania, described in 2002.

  13. Prosopanche-New World • P. americana -widespread on species of Prosopis (Fabaceae). • P. bonacinae-Diversity of hosts.

  14. Prosopanche-New World

  15. Hydnora-Old World

  16. Predicted distribution of Gondwanaland paleoherbs

  17. Prosopanche

  18. Prosopanche americana, Cordoba Province, Argentina

  19. Hydnoraceae flowers are chamber flowers

  20. A chamber is present above the stigma. Chamber Prosopanche americana

  21. What is the function of the chamber? Chamber Prosopanche americana

  22. For the insect-- It provides a place for the insect visitor to spend the night. Mating often takes place. Chamber Prosopanche americana

  23. For the plant-- It provides a “holding room” while the flower changes sex. Chamber Prosopanche americana

  24. Flower structure of Prosopanche americana Androecium Gland Stigma Prosopanche americana

  25. Prosopanche americana

  26. Prosopanche americana Pistillate phase Day one

  27. Prosopanche americana Staminate phase Day two

  28. Prosopanche flowers are dichogamous, that is, have distinctly staminate (male) and pistillate (female) phases.

  29. Prosopanche americana Pollinated by a nitulid (Neopocadius nitiduloides) Oxycorynus spp. (weevils) lay eggs in flowers but are not pollinators

  30. Life history of Prosopanche americana Host: Prosopis alba Male phase Femalephase Fruit

  31. Hydnora

  32. Floral Syndromes and Hosts Hydnora johannis Acacia spp. (Fabaceae) Beetles Hydnora africana Euphorbia spp. Beetles Hydnora esculenta ??? ??? Hydnora triceps Euphorbia dregeana ???

  33. Hydnora africana- osmophores are elongate Osmophores Hydnora triceps-osmophores are in folds of perianth Hydnora abyssinca-osmophores are tips of perianth Oldest flowers on left

  34. Is the osmophore in H. johannis unique? Mature flower Immature flower

  35. Recent research on Hydnora triceps

  36. Namaqualand

  37. Namaqualand

  38. Port Nolloth Center of diamond dredging, diamond smuggling….and Hydnora diversity.

  39. Succulent Karoo • This biome is characterized by low but reliable rainfall (20-290 mm year), chiefly in the winter. It has the highest species richness for any semiarid vegetation and a high rate of endemism, exceeding 50% (Milton et al., 1997). The dominant plants in the sandy soil of these low hills are shrubby species of Euphorbia.

  40. Succulent Karoo near Port Nolloth, South Africa Rainy season, September 2001

  41. Euphorbia dregeana, host of H. triceps

  42. Dry Season, December 2002

  43. Distribution of Hydnora africana is related to that of its common host, Euphorbia gregaria Assumption: true for other species as well.

  44. History of Discovery • Hydnora triceps first described by Drège in 1833 from material collected near Okiep in Namaqualand. Only ten specimens extant, all from the Okiep region. • Last seen in 1888.

  45. History of Discovery • Johann Visser rediscovered H. triceps in 1988. Died shortly thereafter • Eight populations located 1999-2001 in South Africa, near Port Nolloth. • Discovered in Namibia in September 2001.

  46. Is the distribution of the parasite dependent upon the host? Hydnora triceps found only on E. dregeana Namibia Rosh Pinnah--First Namibian collection South Africa Orange River Previously known collections of H. triceps at red arrow

  47. The sole evidence of Hydnora triceps

  48. ??

  49. The Strangest Plants in the World!

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