Sequoia (genus)

Sequoia
Temporal range: Jurassic to present
Redwoods in Oakland, California
Scientific classification
Kingdom: Plantae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Cupressaceae
Subfamily: Sequoioideae
Genus: Sequoia
Endl., conserved name
Species
Synonyms[1]
  • Condylocarpus Salisb. ex Lamb.
  • Gigantabies J.Nelson
Del Norte Titan, one of the top ten largest coast redwoods – Sequoia sempervirens

Sequoia is a genus of redwood coniferous trees in the subfamily Sequoioideae of the family Cupressaceae. The only extant species of the genus is Sequoia sempervirens in the Northern California coastal forests ecoregion of Northern California and Southwestern Oregon in the United States.[1][2] The two other genera, Sequoiadendron and Metasequoia, in the subfamily Sequoioideae are closely related to Sequoia. It includes the largest trees in the world.

Several extinct species have been named from fossils, including Sequoia affinis, Sequoia chinensis of China, Sequoia langsdorfii, Sequoia dakotensis of South Dakota (Maastrichtian), and Sequoia magnifica.

Etymology

The name Sequoia was first published as a genus name by the Austrian botanist Stephan Endlicher in 1847.[3] However, he left no specific reasons for choosing that name, and there is no record of anyone else speaking to him about its origin.

The most common modern guess is that Endlicher, a published linguist as well as a botanist, named the genus in honor of Sequoyah, the inventor of the first Cherokee writing system.[4] As far back as the 1860s, it has also been suggested that the name is instead an alteration of the Latin word for "sequence", since the species is known to be a follower or remnant of massive ancient, extinct species, and thus the next in a sequence.[5]

However, in a 2012 article, author Gary Lowe argues that Endlicher would not have had the knowledge to conceive of Sequoia sempervirens as the successor to a fossil sequence, and that he more likely saw it as completing a morphological sequence of species in regards to seeds per cone scale.[5]

Paleontology

The genus Sequoia first appears in the fossil record as Sequoia jeholensis, found in Jurassic deposits of South Manchuria.[6] By the late Cretaceous it was already established in Europe, parts of China, and western North America. Comparisons among fossils and modern organisms suggest that by this period Sequoia had already evolved a greater tracheid diameter that allowed it to reach the great heights characteristic of the modern Sequoia sempervirens (coast redwood).

Sequoia was not dominant in the tropical high northern latitudes, like Metasequoia, a redwood whose deciduous habit gave it a significant adaptive advantage in an environment with 3 months of continuous darkness.[7] However, there still was prolonged range overlap between Sequoia and Metasequoia which could have led to hybridization events that created the modern hexaploid Sequoia sempervirens.[6][8]

A general cooling trend by the late Eocene and Oligocene reduced the northern ranges of Sequoia. By the end of the Miocene and beginning of the Pliocene, Sequoia fossils were morphologically identical to the modern Sequoia sempervirens.[6] Continued cooling in the Pliocene meant that Sequoia, which is extremely intolerant to frost due to the high water content of its tissues, also became locally extinct in response to the extreme cooling of Europe and Asia[9] In western North America it continued to move south through coastal Oregon and California, surviving due to the abundant rainfall and mild seasons.[9] The Sierra Nevada orogeny further isolated Sequoia because the snowy mountain peaks prevented eastward expansion.[9] The Pleistocene and Holocene distributions are likely nearly identical to the modern S. sempervirens distributions.

See also

References

  1. 1 2 Kew World Checklist of Selected Plant Families
  2. ↑ Biota of North America Program 2013 county distribution map
  3. ↑ Endlicher, Stephan (1847). Synopsis Coniferarum. St. Gallen: Scheitlin & Zollikofer.
  4. ↑ Sierra Nevada - The Naturalist's Companion. University of California Press. 1 June 2000. p. 55. ISBN 978-0-520-92549-6.
  5. 1 2 Lowe, Gary D. (2012). "Endlicher's sequence: the naming of the genus Sequoia" (PDF). Fremontia. 40 (1 & 2): 25–35. Retrieved January 1, 2014.
  6. 1 2 3 M. R. Ahuja & D. B. Neale (2002). "Origins of polyploidy in coast redwood (Sequoia sempervirens) and relationship of coast redwood to other genera of Taxodiaceae" (PDF). Silvae Genetica. 51 (2–3): 93–100.
  7. ↑ Richard Jagels & Maria A. Equiza (2005). "Competitive advantages of Metasequoia in warm high latitudes". In Ben A. LePage, Christopher James Williams & Hong Yang. The Geobiology and Ecology of Metasequoia. Topics in geobiology. 22. Dordrecht, the Netherlands: Springer. pp. 335–349. ISBN 1-4020-2631-5.
  8. ↑ Deborah L. Rogers (2000). "Genotypic diversity and clone size in old-growth populations of coast redwood (Sequoia sempervirens)". Canadian Journal of Botany. 78 (11): 1408–1419. doi:10.1139/cjb-78-11-1408.
  9. 1 2 3 James Arthur Snyder (1992). The ecology of Sequoia sempervirens: an addendum to "On the edge: nature's last stand for coast redwoods" (M.A. thesis). San Jose State University.
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