The Laricoideae are a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus Genus ( plural genera ) is a taxonomic rank used in the biological classifica ...

of the

Pinaceae The Pinaceae, or pine family, are conifer trees or shrubs, including many of the well-known conifers of commercial importance such as cedars, firs, hemlocks, larches, pines and spruces. The family is included in the order Pinales, formerly kn ...

, a

Pinophyta 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 ext ...

division Division or divider may refer to: Mathematics *Division (mathematics), the inverse of multiplication *Division algorithm, a method for computing the result of mathematical division Military *Division (military), a formation typically consisting ...

family. They take their name from the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

Larix Larches are deciduous conifers in the genus ''Larix'', of the family Pinaceae (subfamily Laricoideae). Growing from tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains fu ...

'' ( larches), which contains inside most of the species of the

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic ide ...

and is one of only two

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...

genera of the pines complex (together with '' Pseudolarix'', which however belongs to a different subfamily, the Abietoideae). Ecologically important trees, the Laricoideae form pure or mixed

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

associations often dominant in the

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syst ...

s 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

three genera (''

'', ''

Pseudotsuga ''Pseudotsuga'' is a genus of evergreen coniferous trees in the family Pinaceae (subfamily Laricoideae). Common names for species in the genus include Douglas fir, Douglas-fir, Douglas tree, Oregon pine and Bigcone spruce. ''Pseudotsuga menzie ...

'' and ''

Cathaya ''Cathaya'' is a genus in the pine family, Pinaceae, with one known living species, ''Cathaya argyrophylla''. ''Cathaya'' is a member of the subfamily Laricoideae, most closely related to ''Pseudotsuga'' and ''Larix''. A second species, ''C. na ...

'') and its members can be found only in

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

. The various

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

live for the most part in

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...

cold Cold is the presence of low temperature, especially in the atmosphere. In common usage, cold is often a subjective perception. A lower bound to temperature is absolute zero, defined as 0.00K on the Kelvin scale, an absolute thermodynamic ...

climates Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological ...

and are the more northerly

conifers 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 ext ...

; some constitute an important source of

timber Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, w ...

and

non-timber forest product Non-timber forest products (NTFPs) are useful foods, substances, materials and/or commodities obtained from forests other than timber. Harvest ranges from wild collection to farming. They typically include game animals, fur-bearers, nuts, see ...

Description

The

of the

Laricoideae are

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

trees In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are u ...

that can reach the greater heights in the

family (over 100 meters with '' Pseudotsuga menziesii var. menziesii''). The

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

are needle-like and have primary stomatal bands only on the abaxial surface (below the

phloem Phloem (, ) is the living tissue in vascular plants that transports the soluble organic compounds made during photosynthesis and known as ''photosynthates'', in particular the sugar sucrose, to the rest of the plant. This transport process is c ...

vessels). All members are

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is ...

, with separate sexes on the same

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae excl ...

but in different reproductive structures. The annual

cones A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex. A cone is formed by a set of line segments, half-lines, or lines conn ...

(''strobili'') have no distinct umbo and the scales show a broad base which, at observation, completely hides the

seeds A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm ...

from the abaxial view. These last are whitish and firmly fixed to the wing (this thin membrane also keeps the

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

well attached to the scale during maturation); furthermore, among the typical distinctive features of the group, we have the micropylar fluid of the

strobilus A strobilus (plural: strobili) is a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem. Strobili are often called cones, but some botanists restrict the use of the term cone to th ...

absent, no

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on nat ...

vesicles on the

and the presence, in the vascular cylinder of the young

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...

, of two characteristic small resiniferous canals. The

bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, e ...

and the

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...

of the genera ''

'' and ''

'' have a similar

anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having i ...

and morphology: the reddish color of the

heartwood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin t ...

and the white-yellowish of the sapwood, the high

specific weight The specific weight, also known as the unit weight, is the weight per unit volume of a material. A commonly used value is the specific weight of water on Earth at , which is .National Council of Examiners for Engineering and Surveying (2005). ''Fu ...

compared to other

, the distribution of late and

earlywood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin tha ...

, the presence of resiniferous channels and their localization in the tissuets, the

molecules A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bio ...

that form the

and extractives, the chemical, physical and mechanical properties as well as the class of resistance to the attack of

pathogens In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a ger ...

such as

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...

and

insects Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...

are a clue of a common ancestral origin. Similar between the two genera are also some aspects of the phenology, the degree of shade tolerance, the fire-resistant marbled bark and the appearance of the young shoots.

Taxonomy

The

Laricoideae was described with the actual name by

Robert Knud Friedrich Pilger Robert Knud Friedrich Pilger (3 July 1876, in Helgoland – 1 September 1953, in Berlin)

and

Hans Melchior Hans Melchior (5 August 1894 – 12 March 1984) was a German botanist. Melchior was born in Berlin. He studied botany at Humboldt University of Berlin, Berlin University, became assistant to Gottlieb Haberlandt, G. Haberlandt at the Institute f ...

in late 1954 and subsequently modified by other authors in the course of time as regards the

taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

of belonging. Before that, the genera ''

'', ''

'' and ''

Cedrus ''Cedrus'', common English name cedar, is a genus of coniferous trees in the plant family Pinaceae (subfamily Abietoideae). They are native to the mountains of the western Himalayas and the Mediterranean region, occurring at altitudes of 1,500 ...

'' were gathered in a provisional

called Laricinae, defined for the first time by Melchior and Werdermann always in 1954 (...''“trees that have both short and long shoots, monomorphic leaves, and strobili borne on the short shoots”''...) and rechristened immediately after with the current term. The grouping in this form was confirmed by Hart (1987) through cladistic analysis, but already in 1988 Frankis replaced ''

'' with ''

'' (a genus described for the first time in 1962) in a new classification (now obsolete) that saw

as a distinct twin group compared to ''

'' - ''

''. Historically the Laricoideae were the

of the

comprising the trees with needles inserted both on the macroblasts and on the brachiblasts; for this reason in the past they have been also included in it the genera '' Pseudolarix'' (for a short time) and ''

'', subsequently eliminated following the most recent systematic updates developed on the basis of molecular genetic phylogeny, reproductive morphology, chromosome numbers and

immunology Immunology is a branch of medicineImmunology for Medical Students, Roderick Nairn, Matthew Helbert, Mosby, 2007 and biology that covers the medical study of immune systems in humans, animals, plants and sapient species. In such we can see ther ...

. Currently, based on these studies, there are three genera in the

Laricoideae, of which one of which is monotypic as it consists of only one

Within the

the genera ''

'' and ''

'' are more closely correlated to each other (''

sister taxa In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

'') than ''

''. This evidence is demonstrated by numerous biological and macro-micro morphological similarities between the larches and the Douglas-firs including, but not only, a various tissues common anatomy, immunology of seed protein and the absence of the two air sacs in the

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

, typicals instead of the other

. The similarities between the

grains of the genera ''

'' and ''

'' however do not stop here and include other aspects as: granules not buoyant, atectate, with external wall (''exospore'') granular, pollination drop containing

xylose Xylose ( grc, ξύλον, , "wood") is a sugar first isolated from wood, and named for it. Xylose is classified as a monosaccharide of the aldopentose type, which means that it contains five carbon atoms and includes an aldehyde functional g ...

and the presence of an exine shell during microgametophyte germination. Doyle and O'Leary (1935) furthermore described a pollination process very similar in ''

'' and ''

'' where the granule, which lacks air sacs, lands on an almost stigmatic extension of the integument, the margins of which tend to inroll. The contact with the nucellus may (''

'') or may not (''

'') be needed for

tubes to develop, but the mechanism is almost analogous. The time from pollination to fertilization in these two

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

may be over a year and the granules germination can take months (Little et al., 2014). Pinaceae subfamily

Price et al. he supposed in 1977 that the Laricoideae were a

sister A sister is a woman or a girl who shares one or more parents with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a family, familial relationship, it is sometimes used endearingly to r ...

of the Abietoideae rather than the

Pinoideae 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. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accepts ...

- Piceoideae group and this version was confirmed by Hart (1987), Frankis (1988), Farjon (1990), Wang et al. (2000) and Gernandt et al. (2008), although it has not yet found application in the

literature Literature is any collection of Writing, written work, but it is also used more narrowly for writings specifically considered to be an art form, especially prose fiction, drama, and poetry. In recent centuries, the definition has expanded to ...

Dichotomous key

The dichotomous key to recognizing the

included to the

Laricoideae is relatively simple, since only three of them belong to it and one of these is

. Below is reported the taxonomic identification scheme in the form of a table:

Revisions and research

According to the latest research still in progress, the genus ''

'' would be attributed to the grouping of

pines 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. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garde ...

(

), leaving therefore only ''

'' and ''

'' to forming the

Laricoideae. Furthermore, studying the ''mitochondrial rps3 gene'', Ran et al. (2010) found that ''

'' and ''

'' are evolutionarily sister genera to all other

, highlighting a different (sub-parallel) origin compared than the remaining

. Spellenberg, Earle and Nelson (2014) report that the larches and Douglas firs evolved from the

135

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago ...

and they kept a common

ancestor An ancestor, also known as a forefather, fore-elder or a forebear, is a parent or ( recursively) the parent of an antecedent (i.e., a grandparent, great-grandparent, great-great-grandparent and so forth). ''Ancestor'' is "any person from w ...

until 7

, thus forming a divided and closely related taxonomic line between them compared to the rest of the group, while maintaining a strong degree of kinship with it. For Wang et al (2000), instead, ''

'' differentiated himself from ''

'' in Western

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

about 65 million years ago, in an era between the late

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

and the

Paleocene The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''pala ...

. These revisions and interactions, which would find evidence in

genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar work ...

, however are not universally accepted and many botanics, researchers and scientists still use the previous

classification Classification is a process related to categorization, the process in which ideas and objects are recognized, differentiated and understood. Classification is the grouping of related facts into classes. It may also refer to: Business, organizat ...

waiting for further developments. For other authors, finally, the

Laricoideae would have no taxonomic dignity of its own, recognizing only two large multi-group

clades A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English te ...

(Pinoid and Abietoid) or subfamilies (

and Abietoideae) in their

cladistics Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived cha ...

systems. ''

'', ''

'' and ''

'' would be included in the

complex.

References

Bibliography

*''

, Drawings and Descriptions of the Genera:

Abies Firs (''Abies'') are a genus of 48–56 species of evergreen coniferous trees in the family Pinaceae. They are found on mountains throughout much of North and Central America, Europe, Asia, and North Africa. The genus is most closely re ...

, Pseudolarix, Keteleeria,

Nothotsuga ''Nothotsuga'' is a genus of coniferous trees in the family Pinaceae endemic to China. ''Nothotsuga'' contains only one species, ''Nothotsuga longibracteata'', commonly known as the bristlecone hemlock, which is found in southeastern China, in ...

Tsuga ''Tsuga'' (, from Japanese (), the name of ''Tsuga sieboldii'') is a genus of conifers in the subfamily Abietoideae of Pinaceae, the pine family. The common name hemlock is derived from a perceived similarity in the smell of its crushed foli ...

and

Picea A spruce is a tree of the genus ''Picea'' (), a genus of about 35 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 subfami ...

''. Aljos Farjon. Koeltz Scientific Books, 1990 - 330 pages. * *

External links

Taxonomicon.nl
Subfamily ''Laricoideae'' on taxonomicon.nl
The Gymnosperm Database
– Pinaceae (subfamily ''Laricoideae'')

in ''Pinaceae'' (

Missouri Botanical Garden The Missouri Botanical Garden is a botanical garden located at 4344 Shaw Boulevard in St. Louis, Missouri. It is also known informally as Shaw's Garden for founder and philanthropist Henry Shaw. Its herbarium, with more than 6.6 million ...

)
Subfamily Laricoideae - (Rendle) Pilger & Melchior
in ''BioLib.cz'' {{Authority control Pinaceae Plant subfamilies

Description

Taxonomy

Dichotomous key

Revisions and research

See also

References

Bibliography

External links