Sequoia (genus)

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Sequoia
Del Norte Titan 230.jpg
Del Norte Titan, the fourth largest coast redwood – Sequoia sempervirens
Scientific classification
Kingdom: Plantae
Division: Pinophyta
Class: Pinopsida
Order: Pinales
Family: Cupressaceae
Subfamily: Sequoioideae
Genus: Sequoia
Endl., conserved name
Binomial name
Sequoia sempervirens
(D.Don) Endl.
Synonyms[1]
  • Condylocarpus Salisb. ex Lamb.
  • Gigantabies J.Nelson
Redwoods in Oakland, California
(note Homo sapiens below)

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[edit]

The name Sequoia was first published as a genus name by the botanist and linguist Stephen Endlicher in 1847. Most modern sources say that the genus was named in honor of Sequoyah, a Cherokee scholar and inventor of the first Cherokee writing system.[3] However, Endlicher left no specific reasons for his choosing that name, and there is no record of anyone stating second-hand that they spoke to him about the origin of the name. As far back as the 1860s it has been debated that perhaps instead the name is an alteration of the Latin word for "sequence", since the species is known to be a follower or remnant of massive ancient, extinct species; the next in a sequence.[4]

In an article published in 2012, author Gary Lowe points out that Endlicher would not have had the fossil knowledge to use as a basis for the idea of a sequence in the name, but rather points to what Endlicher perceived as a sequence of morphological characteristics, and how at that time, the species he was describing, Sequoia sempervirens, seemed to complete a sequence of species in regards to seeds per cone scale.[4]

The most common guess as to the origin of the name, though, is that Endlicher, being also a linguist and author on the mechanics of language himself, gave the name as a Latinized tribute to the developer of the original Cherokee system of writing, Sequoyah.[5]

Paleontology[edit]

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[edit]

References[edit]

  1. ^ a b Kew World Checklist of Selected Plant Families
  2. ^ Biota of North America Program 2013 county distribution map
  3. ^ Encyclopaedia Britannica, Inc (1 January 2012). Britannica Student Encyclopedia (A-Z Set). Encyclopaedia Britannica, Inc. p. 70. ISBN 978-1-61535-557-0. 
  4. ^ a b Lowe, Gary D. (2012). "Endlicher's sequence: the naming of the genus Sequoia" (PDF). Fremontia 40 (1 & 2): 25–35. Retrieved January 1, 2014. 
  5. ^ Sierra Nevada - The Naturalist's Companion. University of California Press. 1 June 2000. p. 55. ISBN 978-0-520-92549-6. 
  6. ^ a b c 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. ^ a b c 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.