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

2. Lytton John Musselman Old Dominion University Lytton John Musselman Old Dominion University

3. Features of the family Phylogeny of the family Taxonomy Floral biology Diaspore

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

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. Androecium Gland Stigma Flower structure of Prosopanche americana Prosopanche americana

26. 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 Male phase Female phase Fruit Host: Prosopis alba

31. Hydnora

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

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

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

35. Recent research on Hydnora triceps

37. Namaqualand

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

40. 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.

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

42. Euphorbia dregeana, host of H. triceps

43. Dry Season, December 2002

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

45. 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.

46. 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.

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

48. The sole evidence of Hydnora triceps

49. ??

51. Hydnora triceps flowers underground!!

52. Hydnora triceps is the only known dicot with underground flowers!

53. Hypogeous flowering known in only two genera Rhizanthella gardneri Rogers, endemic to Southwest Australia. Hydnora triceps.

54. Hydnora triceps is dichogamous, that is, flowers are functionally pistillate the first day and functionally staminate the second.

55. Stages in Development Arrows indicate anthesis. Flowers to right are pistillate.

56. Stages in Development Opening to chamber is open on day one Day one

57. Stages in Development Opening to chamber closes on day two Opening to chamber is open on day one Day two Day one

58. Fruits previously unknown.

59. Fruits of Hydnora triceps

60. Fruits hollowed out by unknown animal.

61. Hypogeous flowering and fruiting known only in H. triceps

62. Day one Hydnora africana

63. Day oneDay two

64. Day one-PistillateDay two-Staminate

65. Day one Day two Day two plus

66. Closed antheral ring. Floral visitors can be trapped in flowers when ring closes.

67. Hydnora africana is dichogamous, that is, flowers are functionally pistillate the first day and functionally staminate the second.

68. Fruit of Hydnora africana

69. Antheral ring does not close in H. johannis

70. Is H. johannis dichogamous?

71. Continuing research --Determine pollinators and dispersers --Study population structure --Determine relationship among species

72. Meanwhile, back at home...

73. Can similar pollination syndromes be found in the Aristolochiaceae? Aristolochia macrophylla Hexastylis virginica

74. Aristolochia clematis Note fused androecium

75. With Thanks to... Piet Vorster, Department of Botany Stellenbosch University, Stellenbosch Outstanding Hydnora hunter, Libby Musselman Erika Maass, Department of Biology,University of Namibia, Windhoek