Pachycaul

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Fouquieria columnaris Boojum Tree.jpg
Fouquieria columnaris

Pachycauls are plants with a disproportionately thick trunk, for their height, and relatively few branches. [1] With certain pachycaul species, particularly the more succulent varieties, they are commonly referred to as "caudiciformes", a reference to their trunk development of a moisture-filled caudex for periods of drought. By comparison, trees with thin twigs, such as oaks ( Quercus ), maples ( Acer ) and Eucalyptus , are called leptocauls; those with moderately thick twigs, such as Plumeria , are called mesocauls. Pachycauls can be the product of exceptional primary growth (as with Arecaceae and Cycadaceae) or disproportionate secondary growth, as with the baobabs ( Adansonia ). The word is derived from the Greek pachy- (meaning "thick" or "stout") and the Latin caulis (meaning "stem"). [2]

All of the arboreal (treelike) species of Cactaceae are pachycauls, as are most of the Arecaceae, Cycadaceae and Pandanus . The most extreme pachycauls are the floodplains, or river-bottom, varieties of the African palmyra ( Borassus aethiopum ), with primary growth up to 2.1 m (6 ft 11 in) thick, [3] [4] and the Coquito palm ( Jubaea chilensis ), with its primary growth measuring up to 1.8 m (5 ft 11 in) thick. [5] [6] [7] The most pachycaulous cycad is Cycas thouarsii at up to 150 cm (59 in) diameter. [8] The tallest pachycaul is the Andean wax palm ( Ceroxylon quindiuense ), at heights of up to 66 m (217 ft), [9] and around 41 cm (16 in) in diameter. The most pachycaulous cactus are the barrel cacti ( Echinocactus platyacanthus ), with primary growth up to 1.3 m (4 ft 3 in) diameter. [10] The largest caudiciforme-type pachycaul is the African baobab ( Adansonia digitata ); one specimen of which, called the Glencoe baobab (from Hoedspruit, Limpopo, South Africa) has a basal diameter (not girth) of 16 m (52 ft). [11] However, this particular tree has suffered a severe trauma and is dying. Pachycauls also differ greatly in their rates of growth, from the half-man tree ( Pachypodium namaquanum ) which grows only 5 mm (0.20 in) each year [12] to the palm Pigafetta elata which can grow 2.7 m (8 ft 10 in) or more in one year. [13]

Examples occur in these genera: [14]

See also

References

  1. ↑ Gupta, I. C.; S. K. Gupta (1992). Concepts' Dictionary Of Agricultural Sciences. Concept Publishing Company. p. 348. ISBN   978-81-7022-301-6.
  2. ↑ Stearn, W.T. (1992). Botanical Latin: History, grammar, syntax, terminology and vocabulary, Fourth edition. David and Charles.
  3. ↑ Von Mueller, Ferdinand (1881). Select Extra-tropical Plants. Sydney: Government Printer. p. 50.
  4. ↑ Carder, Dr. Al (2005). Giant Trees of Western America and the World. Madeira Park, British Columbia: Harbour Pub. Co. Ltd. p. 130.
  5. ↑ anonymous (January 1957). "<not recorded>". Principes. 1 (2): 57.
  6. ↑ Caradine, Chris (November 1998). "A Day at Ocoa". The Palm Journal. [no volumes] (143): 20 with photo.
  7. ↑ Riverside (California) Sunday Press Enterprise (September 6, 1964) page 39 Excellent photo with three people for size comparison.
  8. ↑ Earle, Christopher. "Gymnosperm Database - Cycadales" . Retrieved November 24, 2021.
  9. ↑ Corner, Prof. E.J.H. (1966). Natural History of Palms. Berkeley, Calif.: Univ. Calif. Press. p. 289.
  10. ↑ Britton, Nathan L.; Rose, Joseph N. (1963). The Cactaceae - Volume 3 (reprint ed.). New York: Dover Pubs. Inc. p. 170.
  11. ↑ Esterhuyse, Neels; et al. (2001). Remarkable Trees of South Africa. Pretoria: Briza Pubs. pp. 6 (table) and 156 & 159.
  12. ↑ Claassen, Isabel (February 1987). "A Saad Semi-human Succulent". South African Panarama. 32 (2): 24.
  13. ↑ Hodel, Donald R. (July 1993). "Growth of Some Palms in Tahiti". Principes. 37 (3): 376–378.
  14. ↑ Wickens, G. E.; Pat Lowe (2008). The Baobabs: Pachycauls of Africa, Madagascar and Australia. Springer. pp. 139–140. ISBN   978-1-4020-6430-2.


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