Othonna

Othonna
Othonna capensis
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Asterales
Family: Asteraceae
Tribe: Senecioneae[1]
Genus: Othonna
L. (1753)
Type species
Othonna coronopifolia[2]
L.
Synonyms[1]

Othonna is a genus of African plants in the sunflower family.[3][2]

These are evergreen or deciduous geophytes, dwarf succulents or shrubs concentrated in the Western Cape Province of South Africa and also in southern Namibia. A few species occur in summer rainfall parts of southern Africa. The genus is closely allied to Senecio and can be distinguished principally by details of the involucre. Taxonomically, they are in need of a modern revision.

The form or habit of othonnas is very diverse and in this lies much of their appeal to collectors of winter growing succulent plants. The various species may be pachycauls with elongate but proportionately swollen stems, caudiciform caudiciforms or dwarf and compact succulents with short branches. A highly distinctive group is made up tuberous geophytes with subterranean rootstocks and deciduous stems or leaves. Other species are orthodox shrubs.

Leaf diversity is also notable in this genus. A few species possess highly succulent leaves (e.g., O. capensis, O. sedifolia) but most have bifacial leaves that are only slightly succulent. Size and shape is variable, with most species having leaves in the 1-10 cm long range, common shapes being elliptic, lanceolate, oblanceolate or spathulate. The leaf blades may be intricately divided (O. abrotanifolia) or lobed (O. cakilaefolia), amplexicaul or distinctly undulate. Often the leaves are sessile and the lamina is glaucous; leaf margins are entire to coarsely toothed. Some species are dimorphic in that the acaulescent juvenile leaves are very different from the adult leaves that are produced on the flowering stems.

With few exceptions the flowers of othonnas fit the stereotypical "DYC" ("Damned Yellow Composite", a tongue-in-cheek phrase used for a variety of composites) designation. A simple or branched inflorescence gives rise to daisy-like flower heads. The exceptions are a handful of attractive purple-flowered species that are deciduous geophytes. Most if not all species are self-incompatible. The seeds are often proportionately heavy and probably do not travel far from the parent plant without the assistance of brisk winds. In at least some cases the seeds exude a sticky substance when wetted and thus affix themselves to the soil surface, aiding in the establishment of seedlings.

Species[1]
  1. Othonna abrotanifolia
  2. Othonna acutiloba
  3. Othonna alata
  4. Othonna alba
  5. Othonna amplexifolia
  6. Othonna arborescens
  7. Othonna arbuscula
  8. Othonna armiana
  9. Othonna auriculifolia
  10. Othonna brandbergensis
  11. Othonna bulbosa
  12. Othonna burttii
  13. Othonna cacalioides
  14. Othonna cakilefolia
  15. Othonna campanulata
  16. Othonna capensis
  17. Othonna carnosa
  18. Othonna chromochaeta
  19. Othonna ciliata
  20. Othonna clavifolia
  21. Othonna coronopifolia
  22. Othonna cuneata
  23. Othonna cyclophylla
  24. Othonna cylindrica
  25. Othonna decurrens
  26. Othonna dentata
  27. Othonna digitata
  28. Othonna divaricata
  29. Othonna diversifolia
  30. Othonna elliptica
  31. Othonna eriocarpa
  32. Othonna euphorbioides
  33. Othonna filicaulis
  34. Othonna floribunda
  35. Othonna frutescens
  36. Othonna furcata
  37. Othonna graveolens
  38. Othonna gymnodiscus
  39. Othonna hallii
  40. Othonna hederifolia
  41. Othonna herrei
  42. Othonna heterophylla
  43. Othonna huillensis
  44. Othonna humilis
  45. Othonna incisa
  46. Othonna intermedia
  47. Othonna lasiocarpa
  48. Othonna laureola
  49. Othonna lepidocaulis
  50. Othonna leptodactyla
  51. Othonna lineariifolia
  52. Othonna lingua
  53. Othonna lobata
  54. Othonna lyrata
  55. Othonna macrophylla
  56. Othonna macrosperma
  57. Othonna membranifolia
  58. Othonna mucronata
  59. Othonna multicaulis
  60. Othonna nana
  61. Othonna natalensis
  62. Othonna nodulosa
  63. Othonna obtusiloba
  64. Othonna oleracea
  65. Othonna opima
  66. Othonna osteospermoides
  67. Othonna ovalifolia
  68. Othonna pachypoda
  69. Othonna papaveroides
  70. Othonna parviflora
  71. Othonna patula
  72. Othonna pavelkae
  73. Othonna pavonia
  74. Othonna perfoliata
  75. Othonna petiolaris
  76. Othonna pinnata
  77. Othonna plantaginea
  78. Othonna pluridentata
  79. Othonna primulina
  80. Othonna protecta
  81. Othonna pteronioides
  82. Othonna purpurascens
  83. Othonna pygmaea
  84. Othonna quercifolia
  85. Othonna quinquedentata
  86. Othonna quinqueradiata
  87. Othonna ramulosa
  88. Othonna rechingeri
  89. Othonna reticulata
  90. Othonna retrofracta
  91. Othonna retrorsa
  92. Othonna rhamnoides
  93. Othonna rosea
  94. Othonna rotundifolia
  95. Othonna rufibarbis
  96. Othonna sedifolia
  97. Othonna semicalva
  98. Othonna sonchifolia
  99. Othonna sparsiflora
  100. Othonna spinescens
  101. Othonna stenophylla
  102. Othonna taraxacoides
  103. Othonna tephrosioides
  104. Othonna tortuosa
  105. Othonna trinervia
  106. Othonna triplinervia
  107. Othonna umbelliformis
  108. Othonna vestita
  109. Othonna viminea
  110. Othonna whyteana
  111. Othonna zeyheri

References

  1. 1 2 3 Flann, C (ed) 2009+ Global Compositae Checklist
  2. 1 2 Tropicos, Othonna L.
  3. ↑ Linnaeus, Carl von. 1753. Species Plantarum 2: 924-926 in Latin

External links

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