Pinaceae Temporal range: | |
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Larix (golden), Abies (central foreground) and Pinus (right foreground) | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Gymnospermae |
Division: | Pinophyta |
Class: | Pinopsida |
Order: | Pinales |
Family: | Pinaceae Lindley 1836 |
Genera | |
Synonyms | |
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The Pinaceae ( /pɪˈneɪsiːˌiː,-siˌaɪ/ ), or pine family, are conifer trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, piñons, larches, pines and spruces. The family is included in the order Pinales, formerly known as Coniferales. Pinaceae have distinctive cones with woody scales bearing typically two ovules, and are supported as monophyletic by both morphological trait and genetic analysis. [1] They are the largest extant conifer family in species diversity, with between 220 and 250 species (depending on taxonomic opinion) in 11 genera, [2] and the second-largest (after Cupressaceae) in geographical range, found in most of the Northern Hemisphere, with the majority of the species in temperate climates, but ranging from subarctic to tropical. The family often forms the dominant component of boreal, coastal, and montane forests. One species, Pinus merkusii , grows just south of the equator in Southeast Asia. [3] Major centres of diversity are found in the mountains of southwest China, Mexico, central Japan, and California.
Members of the family Pinaceae are trees (rarely shrubs) growing from 2 to 100 metres (7 to 300 feet) tall, mostly evergreen (except the deciduous Larix and Pseudolarix ), resinous, monoecious, with subopposite or whorled branches, and spirally arranged, linear (needle-like) leaves. [2] The embryos of Pinaceae have three to 24 cotyledons.
The female cones are large and usually woody, 2–60 centimetres (1–24 inches) long, with numerous spirally arranged scales, and two winged seeds on each scale. The male cones are small, 0.5–6 cm (1⁄4–2+1⁄4 in) long, and fall soon after pollination; pollen dispersal is by wind. Seed dispersal is mostly by wind, but some species have large seeds with reduced wings, and are dispersed by birds. Analysis of Pinaceae cones reveals how selective pressure has shaped the evolution of variable cone size and function throughout the family. Variation in cone size in the family has likely resulted from the variation of seed dispersal mechanisms available in their environments over time. All Pinaceae with seeds weighing less than 90 milligrams are seemingly adapted for wind dispersal. Pines having seeds larger than 100 mg are more likely to have benefited from adaptations that promote animal dispersal, particularly by birds. [4] Pinaceae that persist in areas where tree squirrels are abundant do not seem to have evolved adaptations for bird dispersal.
Boreal conifers have many adaptions for winter. The narrow conical shape of northern conifers, and their downward-drooping limbs help them shed snow, and many of them seasonally alter their biochemistry to make them more resistant to freezing, called "hardening".
Classification of the subfamilies and genera of Pinaceae has been subject to debate in the past. Pinaceae ecology, morphology, and history have all been used as the basis for methods of analyses of the family. An 1891 publication divided the family into two subfamilies, using the number and position of resin canals in the primary vascular region of the young taproot as the primary consideration. In a 1910 publication, the family was divided into two tribes based on the occurrence and type of long–short shoot dimorphism.
A more recent classification divided the subfamilies and genera based on the consideration of features of ovulate cone anatomy among extant and fossil members of the family. Below is an example of how the morphology has been used to classify Pinaceae. The 11 genera are grouped into four subfamilies, based on the microscopical anatomy and the morphology of the cones, pollen, wood, seeds, and leaves: [5]
A revised 2018 phylogeny places Cathaya as sister to the pines rather than in the Laricoidae subfamily with Larix and Pseudotsuga.
Ran et al. 2018 [6] & Leslie et al. 2018 [7] [8] | Stull et al. 2021 [9] [10] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Multiple molecular studies indicate that in contrast to previous classifications placing it outside the conifers, Gnetophyta may in fact be the sister group to the Pinaceae, with both lineages having diverged during the early-mid Carboniferous. This is known as the "gnepine" hypothesis. [11] [12]
Pinaceae is estimated to have diverged from other conifer groups during the late Carboniferous ~313 million years ago. [13] Various possible stem-group relatives have been reported from as early as the Late Permian (Lopingian) The extinct conifer cone genus Schizolepidopsis likely represent stem-group members of the Pinaceae, the first good records of which are in the Middle-Late Triassic, with abundant records during the Jurassic across Eurasia. [14] [15] The oldest crown group (descendant of the last common ancestor of all living species) member of Pinaceae is the cone Eathiestrobus , known from the Upper Jurassic (lower Kimmeridgian, 157.3-154.7 million years ago) of Scotland, [16] which likely belongs to the pinoid grouping of the family. [17] [15] Pinaceae rapidly radiated during the Early Cretaceous. [13] Members of the modern genera Pinus (pines), Picea (spruce) and Cedrus (cedar) first appear during the Early Cretaceous. [18] [19] [20] The extinct Cretaceous genera Pseudoaraucaria and Obirastrobus appear to be members of Abietoideae, while Pityostrobus appears to be non-monophyletic, containing many disparately related members of Pinaceae. [17] While Pinaceae, and indeed all of its subfamilies, substantially predate the break up of the super-continent Pangea, its distribution was limited to the northern Laurasia. During the Cenozoic, Pinaceae had higher rates of species turnover than Southern Hemisphere conifers, thought to be driven by range shifts in response to glacial cycles. [21]
External stresses on plants have the ability to change the structure and composition of forest ecosystems. Common external stress that Pinaceae experience are herbivore and pathogen attack which often leads to tree death. [22] In order to combat these stresses, trees need to adapt or evolve defenses against these stresses. Pinaceae have evolved a myriad of mechanical and chemical defenses, or a combination of the two, in order to protect themselves against antagonists. [23] Pinaceae have the ability to up-regulate a combination of constitutive mechanical and chemical strategies to further their defenses. [24]
Pinaceae defenses are prevalent in the bark of the trees. This part of the tree contributes a complex defensive boundary against external antagonists. [25] Constitutive and induced defenses are both found in the bark. [25] [26] [27]
Constitutive defenses are typically the first line of defenses used against antagonists and can include sclerified cells, lignified periderm cells, and secondary compounds such as phenolics and resins. [28] [25] [26] Constitutive defenses are always expressed and offer immediate protection from invaders but could also be defeated by antagonists that have evolved adaptations to these defense mechanisms. [28] [25] One of the common secondary compounds used by Pinaceae are phenolics or polyphenols. These secondary compounds are preserved in vacuoles of polyphenolic parenchyma cells (PP) in the secondary phloem. [29] [27]
Induced defense responses need to be activated by certain cues, such as herbivore damage or other biotic signals. [28]
A common induced defense mechanism used by Pinaceae is resins. [30] Resins are also one of the primary defenses used against attack. [23] Resins are short term defenses that are composed of a complex combination of volatile mono- (C10) and sesquiterpenes (C15) and nonvolatile diterpene resin acids (C20). [23] [30] They are produced and stored in specialized secretory areas known as resin ducts, resin blisters, or resin cavities. [30] Resins have the ability to wash away, trap, fend off antagonists, and are also involved in wound sealing. [29] They are an effective defense mechanism because they have toxic and inhibitory effects on invaders, such as insects or pathogens. [31] Resins could have developed as an evolutionary defense against bark beetle attacks. [30] One well researched resin present in Pinaceae is oleoresin. Oleoresin had been found to be a valuable part of the conifer defense mechanism against biotic attacks. [31] They are found in secretory tissues in tree stems, roots, and leaves. [31] Oleoresin is also needed in order to classify conifers. [31]
The topic of defense mechanisms within family Pinaceae is a very active area of study with numerous studies being conducted. Many of these studies use methyl jasmonate (MJ) as an antagonist. [26] [27] [32] Methyl jasmonate is known to be able to induce defense responses in the stems of multiple Pinaceae species. [26] [32] It has been found that MJ stimulated the activation of PP cells and formation of xylem traumatic resin ducts (TD). These are structures that are involved in the release of phenolics and resins, both forms of defense mechanism. [26] [27]
A pine is any conifer tree or shrub in the genus Pinus of the family Pinaceae. Pinus is the sole genus in the subfamily Pinoideae.
Cedrus, with the common English name cedar, is a genus of coniferous trees in the plant family Pinaceae. They are native to the mountains of the western Himalayas and the Mediterranean region, occurring at altitudes of 1,500–3,200 m in the Himalayas and 1,000–2,200 m in the Mediterranean.
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta, also known as Coniferophyta or Coniferae. The division contains a single extant class, Pinopsida. All extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews. As of 2002, Pinophyta contained seven families, 60 to 65 genera, and more than 600 living species.
A spruce is a tree of the genus Picea, a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. Picea is the sole genus in the subfamily Piceoideae. Spruces are large trees, from about 20 to 60 m tall when mature, and have whorled branches and conical form.
Araucariaceae – also known as araucarians – is a family of coniferous trees, with three living genera, Araucaria, Agathis, and Wollemia. While the family was distributed globally during the Jurassic and Cretaceous periods, in their native distribution they are now largely confined to the Southern Hemisphere, except for a few species of Agathis in Southeast Asia.
Gnetophyta is a division of plants, grouped within the gymnosperms, that consists of some 70 species across the three relict genera: Gnetum, Welwitschia, and Ephedra. The earliest unambiguous records of the group date to the Jurassic, and they achieved their highest diversity during the Early Cretaceous. The primary difference between gnetophytes and other gymnosperms is the presence of vessel elements, a system of small tubes (xylem) that transport water within the plant, similar to those found in flowering plants. Because of this, gnetophytes were once thought to be the closest gymnosperm relatives to flowering plants, but more recent molecular studies have brought this hypothesis into question, with many recent phylogenies finding them to be nested within the conifers.
The gymnosperms are a group of seed-producing plants that includes conifers, cycads, Ginkgo, and gnetophytes, forming the clade Gymnospermae. The term gymnosperm comes from the composite word in Greek: γυμνόσπερμος, literally meaning 'naked seeds'. The name is based on the unenclosed condition of their seeds. The non-encased condition of their seeds contrasts with the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or on their own as in yew, Torreya, Ginkgo. Gymnosperm lifecycles involve alternation of generations. They have a dominant diploid sporophyte phase and a reduced haploid gametophyte phase which is dependent on the sporophytic phase. The term "gymnosperm" is often used in paleobotany to refer to all non-angiosperm seed plants. In that case, to specify the modern monophyletic group of gymnosperms, the term Acrogymnospermae is sometimes used.
Araucaria is a genus of evergreen coniferous trees in the family Araucariaceae. While today they are largely confined to the Southern Hemisphere, during the Jurassic and Cretaceous they were distributed globally. There are 20 extant species in New Caledonia, Norfolk Island, eastern Australia, New Guinea, Argentina, Brazil and Chile.
Cupressaceae is a conifer family, the cypress, with worldwide distribution. The family includes 27–30 genera, which include the junipers and redwoods, with about 130–140 species in total. They are monoecious, subdioecious or (rarely) dioecious trees and shrubs up to 116 m (381 ft) tall. The bark of mature trees is commonly orange- to red-brown and of stringy texture, often flaking or peeling in vertical strips, but smooth, scaly or hard and square-cracked in some species.
Pinus lambertiana is the tallest and most massive pine tree, and has the longest cones of any conifer. The species name lambertiana was given by the Scottish botanist David Douglas, who named the tree in honour of the English botanist, Aylmer Bourke Lambert. It is native to coastal and inland mountain areas along the Pacific coast of North America, as far north as Oregon and as far south as Baja California in Mexico.
Pinus serotina, the pond pine, black bark pine, bay pine,marsh pine, or pocosin pine, is a pine tree found along the Southeastern portion of the Atlantic coastal plain of the United States, from southern New Jersey south to Florida and west to southern Alabama. Pond pine distribution may be starting to spread west towards Mississippi and Tennessee.
Pinus pinaster, the maritime pine or cluster pine, is a pine native to the south Atlantic Europe region and parts of the western Mediterranean. It is a hard, fast growing pine bearing small seeds with large wings.
Methyl jasmonate is a volatile organic compound used in plant defense and many diverse developmental pathways such as seed germination, root growth, flowering, fruit ripening, and senescence. Methyl jasmonate is derived from jasmonic acid and the reaction is catalyzed by S-adenosyl-L-methionine:jasmonic acid carboxyl methyltransferase.
Serotiny in botany simply means 'following' or 'later'.
Pinus matthewsii is an extinct species of conifer in the pine family. The species is solely known from the Pliocene sediments exposed at Ch’ijee's Bluff on the Porcupine River near Old Crow, Yukon, Canada.
The Laricoideae are a subfamily of the Pinaceae, a Pinophyta division family. They take their name from the genus Larix (larches), which contains inside most of the species of the group and is one of only two deciduous genera of the pines complex. Ecologically important trees, the Laricoideae form pure or mixed forest associations often dominant in the ecosystems in which they are present, thanks also to their biological adaptations to natural disturbances, to reproductive strategies put in place and high average longevity of the individuals. Currently are assigned to this subfamily three genera and its members can be found only in Northern Hemisphere. The various species live for the most part in temperate or cold climates and are the more northerly conifers; some constitute an important source of timber and non-timber forest products.
Eathiestrobus mackenziei is a fossil pine cone found in the Kimmeridge Clay Formation near Eathie, on the Black Isle in Scotland. It is the oldest fossil pine currently known.
Pararaucaria is a genus of conifer cone belonging to the extinct family Cheirolepidiaceae. Fossils are known from the Lower Jurassic to Early Cretaceous of North America, Europe, South America and Asia. It is associated with Brachyphyllum-type foliage.
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