| Sequoia | |
|---|---|
 | |
| Sequoia sempervirens | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Cupressales |
| Family: | Cupressaceae |
| Subfamily: | Sequoioideae |
| Genus: | Sequoia Endl. nom. cons. |
| Type species | |
| Sequoia sempervirens | |
| Species | |
 | |
| Natural ranges ofSequoia andSequiodendron green -Sequoia sempervirens red -Sequoiadendron giganteum | |
| Synonyms[1] | |
| |
Sequoia is agenus ofredwoodconiferous trees in the subfamilySequoioideae of the familyCupressaceae. The onlyextant species of the genus isSequoia sempervirens in theNorthern California coastal forests ecoregion ofNorthern California andSouthwestern Oregon in theUnited States.[1][2] The two other genera in the subfamily Sequoioideae,Sequoiadendron andMetasequoia, are closely related toSequoia. It includes thetallest trees, as well as the heaviest, in the world.
Severalextinctspecies have been named fromfossils, includingSequoia affinis(Western North America) andSequoia magnifica (petrified wood from the Yellowstone National Park area).
The nameSequoia was first published as a genus name by the Austrian botanistStephan 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.[citation needed]
Beginning in the 1860s, it was suggested that the name is a derivation from the Latin word for "sequence", since the species was thought to be a follower or remnant of massive ancient, extinct species, and thus the next in a sequence.[4]
However, in a 2012 article, author Gary Lowe argues that Endlicher would not have had the knowledge to conceive ofSequoia sempervirens as the successor to a fossil sequence, and that he more likely saw it, within the framework of his taxonomic arrangements, as completing amorphological sequence of species in regards to the number of seeds per cone scale.[4]
In 2017, Nancy Muleady-Mecham of Northern Arizona University, after extensive research with original documents in Austria, claimed to find a positive link to the personSequoyah (the inventor of theCherokee writing system) and Endlicher, as well as information that the use of the Latinsequor would not have been correct.[5] However there are debilitating limitations to the arguments presented in the 2017 article. The alleged positive link is based on a similarity in pronunciation of the words "Sequoyah" and "Sequoia": valid to persons who think in English, but not those that think in German or Latin. Endlicher could not have known how Sequoyah's name was pronounced in Cherokee since he did not have the opportunity to hear spoken Cherokee. The claimed use of Latin ignores Endlicher's philological background and familiarity with the Latin of the ancient manuscripts in the royal library on which he extensively published. Endlicher's Botanical Latin prefix in the genus name Sequoia was derived from the Latin verb "sequor", and was not a conjugation of the verb.[6]
Sequoia jeholensis is the oldest recorded member of the genusSequoia (along withSequoia portlandica, but this name is anomen dubium), known from theJiufotang Formation (Lower Cretaceous) and theJiulongshan Formation (Middle Jurassic) of China.[7] By the lateCretaceous the ancestral sequoias were established inEurope, parts ofChina, and westernNorth America.[citation needed] Comparisons among fossils and modern organisms suggest that by this periodSequoia ancestors had already evolved a greatertracheid diameter that allowed it to reach the great heights characteristic of the modernSequoia sempervirens (coast redwood) andSequoiadendron giganteum (giant sequoia).[citation needed]
Sequoia ancestors were not dominant in the tropical high northern latitudes, likeMetasequoia, a redwood whosedeciduous habit gave it a significant adaptive advantage in an environment with 3 months of continuous darkness.[8] However, there still was possibly prolonged range overlap betweenSequoia andMetasequoia which could have led to hybridization events that created the modernhexaploidSequoia sempervirens.[9][10] See also the metastudy of the geologic history of the giant sequoia and the coast redwood.[11]
A general cooling trend by the lateEocene andOligocene reduced the northern ranges of ancestralSequoia. By the end of theMiocene and beginning of thePliocene,Sequoia fossils were morphologically identical to the modernSequoia sempervirens.[9] Continued cooling in the Pliocene meant thatSequoia, 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.[12] Pollen sampling of sediments found in Hungary indicates the local extinction of genusSequoia approximately 2.7 million years ago in the first part of the Pliocene.[13] In western North America it continued to move south through coastalOregon andCalifornia, surviving due to the abundant rainfall and mild seasons.[12] TheSierra Nevadaorogeny further isolatedSequoia because the snowy mountain peaks prevented eastward expansion.[12] ThePleistocene andHolocene distributions are likely nearly identical to the modernS. sempervirens distributions.[citation needed]
A number of fossil taxa originally named asSequoia species have subsequently been reidentified into other genera.
