Quercus subg. Quercus

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Quercus subg. Quercus
1. English Oak (Quercus robur) (3607652442).jpg
Quercus robur (type species) growing in England
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fagales
Family: Fagaceae
Genus: Quercus
Subgenus: Quercus subg. Quercus
Sections [1]
  • Quercus sect. LobataeLoudon
  • Quercus sect. PonticaeStef.
  • Quercus sect. Protobalanus(Trelease) O.Schwarz [2]
  • Quercus sect. Quercus
  • Quercus sect. VirentesLoudon

Quercus subgenus Quercus is one of the two subgenera into which the genus Quercus was divided in a 2017 classification (the other being subgenus Cerris). It contains about 190 species divided among five sections. It may be called the New World clade or the high-latitude clade; most species are native to the Americas, the others being found in Eurasia and northernmost North Africa.

Contents

Description

Members of subgenus Quercus are distinguished from members of subgenus Cerris by few morphological features, their separation being largely determined by molecular phylogenetic evidence. All are trees or shrubs bearing acorn-like fruit in which a cup covers at least the base of the nut. The outer structure of the mature pollen is one feature that distinguishes the two subgenera: in subgenus Quercus, the small folds or wrinkles (rugulae) are obscured by sporopollenin, whereas in subgenus Cerris, the rugulae are visible or at most weakly obscured. [1]

The two subgenera are also distinguished to some extent by their different distributions. Subgenus Quercus occurs mainly in the Americas, with some species native to Eurasia and North Africa, and may be called the New World clade or the high-latitude clade. Subgenus Cerris is primarily Eurasian, with a few species in North Africa, and may be called the Old World clade or the mid-latitude clade. [1]

Taxonomy

Phylogeny

The following cladogram summarizes the relationships that Denk et al. used to draw up their 2017 classification: [1]

Quercus
subg. Quercus

sect. Lobatae

sect. Protobalanus

sect. Ponticae

sect. Virentes

sect. Quercus

subg. Cerris

Section Lobatae

Quercus sect. Lobatae was established by John Claudius Loudon in 1830. [3] The section, or part of it, has also been treated under names including Quercus sect. RubraeLoudon and Quercus sect. ErythrobalanusSpach. It has also been treated as the subgenus Erythrobalanus and as the full genus Erythrobalanus(Spach) O.Schwarz. Its members may be called red oaks. [1]

The perianth of the pistillate flowers has a characteristic flange-like shape. The staminate flowers have up to six stamens. The stalk connecting the perianth to the ovary is cone-shaped and often has rings. The acorns mature in two years, rarely in one year. The 'cup' (cupule) of the acorn is fused with its stalk (peduncule) forming a connective piece. Both the connective piece and the cup are covered with small triangular scales, mostly thin and membranous with broadly angled tips. The leaves typically have teeth with bristle-like extensions, or just bristles in leaves without teeth. [1]

The section contains about 125 species native to Northern America (including Mexico), Central America, and Colombia in South America. [1] The red oaks of Mexico are one of the groups of oaks that have most rapidly diversified into different species. Molecular evidence suggests that there are significant numbers of undescribed Quercus species in Mexico, so the number of known species in the section is likely to be an underestimate of the total diversity. [4]

Section Protobalanus

Quercus sect. Protobalanus was first established as a subgenus by William Trelease in 1922 and then later treated as a section by Otto Karl Anton Schwarz in 1936 and Aimée Antoinette Camus in 1938. [1] [note 1]

The staminate flowers have eight to ten stamens. The pollen ornamentation has only small wrinkles or folds (verrucae). The acorns mature after two years. The cup (cupule) at the base of the acorn has triangular scales that are fused at the base and have sharp angled tips. The scales are thick and compressed into rings, often forming small bumps, that may be obscured by glandular hairs. The leaf teeth end in spines. [1]

The section contains only five species, native to southwestern North America and northwestern Mexico. [1]

Section Ponticae

Quercus sect. Ponticae was first established by Boris Stefanoff in 1930. It has also been treated as a subsection and a series, including under the name Q. ser. SadlerianaeTrelease. [1]

Species are shrubs or small trees, with rhizomes. The staminate catkins are up to 10 cm long. The cup (cupule) at the base of the acorn has scales with sharp angled ends. The leaves are either evergreen or deciduous, with simple or compound teeth. The leaf buds are large, enclosed in loosely attached scales. [1]

There are only two species, Quercus pontica and Quercus sadleriana . [5] They have disjoint distributions. Quercus pontica is native to mountainous areas of north-eastern Turkey and western Georgia. Quercus sadleriana is native to northern-most California and southern-most Oregon in the United States. [1]

Section Virentes

Quercus sect. Virentes was first established by John Claudius Loudon in 1838. It has also been treated as a series. [1] Members of the section may be called live oaks. [6]

Species are trees or rhizomatous shrubs. They are evergreen or brevideciduous. The acorns mature in a year. The cup at the base of the acorn has narrowly triangular scales, with thin keels, at most small bumps (tubercules), and sharp angled ends. The leaves are evergreen or almost so. A distinctive feature of the section is that the germinating seed has fused seed leaves (cotyledons) and an elongated stem above the cotyledons (the epicotyl) that forms a tube, while the stem below the cotyledons (the hypocotyl) is tuberous. [1]

The section contains seven species, native to south-eastern Northern America, Mexico, the West Indies (Cuba), and Central America. [1]

Section Quercus

Quercus sect. Quercus has been known, either in whole or part, by a variety of names in the past, including Quercus sect. Albae, Quercus sect. Macrocarpae and Quercus sect. Mesobalanus. Members of the section may be called white oaks. The section includes all white oaks from North America (treated by Trelease as subgenus Leucobalanus). [1]

The staminate flowers have seven or more stamens. The acorns mature in one year. The seed leaves (cotyledons) are either free or fused together. The cup at the base of the acorn has thickened triangular scales that are either free or fused at the base and have sharp angled tips. The scales have keels and are often covered with small bumps (tuberculate). The leaf teeth typically do not have either bristle-like or spiny tips. [1]

There are about 150 species, native to Northern America, Mexico, Central America, western Eurasia, East Asia, and North Africa. [1]

Notes

  1. ↑ At page 23, Denk et al. have only the surnames "Schwarz" and "Camus", but these are the standard botanical abbreviations for the wrong authors. "Schwarz" should be "O. Schwarz", [note 2] standard abbreviation "O.Schwarz". [note 3] "Camus" should be "A.Camus". [note 4]

Related Research Articles

<span class="mw-page-title-main">Oak</span> Tree or shrub in the genus Quercus

An oak is a hardwood tree or shrub in the genus Quercus of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisphere; it includes some 500 species, both deciduous and evergreen. Fossil oaks date back to the Middle Eocene. Molecular phylogeny shows that the genus is divided into Old World and New World clades, but many oak species hybridise freely, making the genus's history difficult to resolve.

<i>Quercus lamellosa</i> Species of tree

Quercus lamellosa is a species of oak (Quercus) native to the Himalaya and adjoining mountains from Tibet and Nepal east as far as Guangxi and northern Thailand, growing at altitudes of 1300–2500 m. The Lepcha of Sikkim call it book koong. It is placed in subgenus Cerris, section Cyclobalanopsis.

<i>Quercus myrsinifolia</i> Species of oak tree

Quercus myrsinifolia is an Asian species of tree in the beech family Fagaceae. It has several common names, including bamboo-leaf oak, Chinese evergreen oak, and Chinese ring-cupped oak. Its Chinese name is 小叶青冈; pinyin: xiǎo yè qīng gāng, which means little leaf ring-cupped oak, in Japan it is called white oak and in Korea it is known as gasinamu (가시나무). It is native to east central and southeast China, Japan, Korea, Laos, northern Thailand, and Vietnam. It is placed in subgenus Cerris, section Cyclobalanopsis.

Quercus asymmetrica is an oak tree species in the beech family Fagaceae. It is found in China and northern Vietnam. It is placed in subgenus Cerris, section Cyclobalanopsis.

<i>Quercus stenophylloides</i> Species of plant

Quercus stenophylloides, also called Arisan oak, is a species of evergreen, broad-leaf tree endemic to Taiwan. It is placed in Quercus subgenus Cerris, section Cyclobalanopsis.

<i>Quercus baloot</i> Species of oak tree

Quercus baloot, the holm oak or holly oak is a rare species of oak that was described by Griffith in 1848. It is classified in subgenus Cerris and section Ilex. It is native to the Himalayas from 1,000–3,000 metres (3,300–9,800 ft).

<i>Quercus argyrotricha</i> Species of tree

Quercus argyrotricha is a rare Chinese species of trees in the beech family. It has been found only in Guizhou Province in southern China. The common name is Chinese for this species is gui zhou qing gang.

Quercus austrocochinchinensis is an uncommon species of tree in the beech family Fagaceae. It has been found in Vietnam and Thailand as well as Yunnan Province in southern China. It is placed in subgenus Cerris, section Cyclobalanopsis.

Quercus blakei is an uncommon species of tree in the beech family Fagaceae. It has been found in Indochina and southern China. It is placed in subgenus Cerris, section Cyclobalanopsis.

Quercus chevalieri is an uncommon species of tree in the beech family Fagaceae. It has been found in Vietnam and also in southern China, in the Provinces of Guangdong, Guangxi, and Yunnan. It is placed in subgenus Cerris, section Cyclobalanopsis.

Quercus poilanei is an Asian species of tree in the family Fagaceae. It has been found in northern Indochina and also in the Province of Guangxi in southern China. It is placed in subgenus Cerris, section Cyclobalanopsis.

Quercus saravanensis is an Asian species of tree in the beech family Fagaceae. It has been found in northern Indochina, and also in the Province of Yunnan in southwestern China. It is placed in subgenus Cerris, section Cyclobalanopsis.

Quercus thorelii is an Asian species of tree in the beech family Fagaceae. The species is named after the French botanist Clovis Thorel. It has been found in Indochina and in southern China. It is placed in subgenus Cerris, section Cyclobalanopsis, the ring-cupped oaks.

Quercus langbianensis is an uncommon oak tree species in the family Fagaceae. It is placed in subgenus Cerris, section Cyclobalanopsis, the ring-cupped oaks. These differ from other Quercus groups in that they have acorns with distinctive cups: usually with substantial rings, made-up of scales that have grown together. This species can be found in sub-tropical and tropical seasonal forests of Vietnam.

Quercus petelotii is the accepted name of an endemic oak tree species in the beech family Fagaceae; there are no known sub-species. It is placed in subgenus Cerris, section Cyclobalanopsis.

<i>Quercus gomeziana</i> Species of oak tree

Quercus gomeziana is a tree species in the beech family Fagaceae. There are no known subspecies. It is placed in subgenus Cerris, section Cyclobalanopsis.

<i>Quercus floribunda</i> Species of plant in the genus Quercus

Quercus floribunda, called the Moru oak or Mohru oak, Tilonj oak and green oak, is a species of oak native to Afghanistan, Pakistan, India's western Himalaya, and Nepal, typically found from 2,000 to 3,000 metres above sea level. It is in the subgenus Cerris, section Ilex. An evergreen tree with a dense crown reaching 30 m (98 ft), it is an important fuelwood and fodder species.

Quercus look, the look oak or Mount Hermon oak, is a species of oak in subgenus Cerris, section Cerris, native to the Levant region of Western Asia, including northern Israel, Lebanon, and Syria. Of the local oak species, it prefers to grow at the highest altitudes, for instance at c. 1800 m on Mount Hermon.

<i>Quercus <span style="font-style:normal;">subg.</span> Cerris</i> Subgenus of the genus Quercus

Quercus subgenus Cerris is one of the two subgenera into which the genus Quercus was divided in a 2017 classification. It contains about 140 species divided among three sections. It may be called the Old World clade or the mid-latitude clade; all species are native to Eurasia and North Africa.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Denk, Thomas; Grimm, Guido W.; Manos, Paul S.; Deng, Min & Hipp, Andrew L. (2017), "An Updated Infrageneric Classification of the Oaks: Review of Previous Taxonomic Schemes and Synthesis of Evolutionary Patterns", in Gil-Pelegrín, Eustaquio; Peguero-Pina, José Javier & Sancho-Knapik, Domingo (eds.), Oaks Physiological Ecology. Exploring the Functional Diversity of Genus Quercus L., Cham.: Springer International Publishing, pp. 13–38, doi:10.1007/978-3-319-69099-5_2, ISBN   978-3-319-69099-5
  2. ↑ Schwarz, O. (1936), "Entwurf zu einem natürlichen System der Cupuliferen und der Gattung Quercus L.", Notizblatt des Königlichen Botanischen Gartens und Museums zu Berlin (in German), 13 (116): 1–22, doi:10.2307/3994908, JSTOR   3994908 , p. 21
  3. ↑ "Quercus sect. Lobatae Loudon", The International Plant Names Index , retrieved 2023-02-25
  4. ↑ Hipp, Andrew L.; Manos, Paul S.; Hahn, Marlene; Avishai, Michael; Bodénès, Cathérine; Cavender-Bares, Jeannine; Crowl, Andrew A.; Deng, Min; Denk, Thomas; Fitz-Gibbon, Sorel; Gailing, Oliver; González-Elizondo, M. Socorro; González-Rodríguez, Antonio; Grimm, Guido W.; Jiang, Xiao-Long; Kremer, Antoine; Lesur, Isabelle; McVay, John D.; Plomion, Christophe; Rodríguez-Correa, Hernando; Schulze, Ernst-Detlef; Simeone, Marco C.; Sork, Victoria L. & Valencia-Avalos, Susana (2020), "Genomic landscape of the global oak phylogeny" (PDF), New Phytologist, 226 (4): 1198–1212, doi:10.1111/nph.16162, PMID   31609470
  5. ↑ Denk, Thomas; Grimm, Guido W.; Manos, Paul S.; Deng, Min & Hipp, Andrew L. (2017-11-02), "Appendix 2.1: An updated infrageneric classification of the oaks" (xls), figshare, doi:10.6084/m9.figshare.5547622.v1 , retrieved 2023-02-17
  6. ↑ Cavender-Bares, Jeannine; González-Rodríguez, Antonio; Eaton, Deren A. R.; Hipp, Andrew A. L.; Beulke, Anne; Manos, Paul S. (2015), "Phylogeny and biogeography of the American live oaks (Quercus subsection Virentes): a genomic and population genetics approach", Molecular Ecology , vol. 24, no. 14, pp. 3668–3687, Bibcode:2015MolEc..24.3668C, doi: 10.1111/mec.13269 , PMID   26095958
  7. "Schwartz, Oskar (1901-1945)", The International Plant Names Index , retrieved 2023-02-25
  8. "Les Chênes: Monographie du genre Quercus", The International Plant Names Index , retrieved 2023-02-25
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