Cupressus pigmaea
Encyclopedia
Cupressus pigmaea is a taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

 of disputed status in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Cupressus
Cupressus
The genus Cupressus is one of several genera within the family Cupressaceae that have the common name cypress; for the others, see cypress. It is considered a polyphyletic group...

endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...

 to certain coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...

al terraces and coastal mountain ranges of Mendocino
Mendocino County, California
Mendocino County is a county located on the north coast of the U.S. state of California, north of the greater San Francisco Bay Area and west of the Central Valley. As of the 2010 census, the population was 87,841, up from 86,265 at the 2000 census...

 and Sonoma Counties
Sonoma County, California
Sonoma County, located on the northern coast of the U.S. state of California, is the largest and northernmost of the nine San Francisco Bay Area counties. Its population at the 2010 census was 483,878. Its largest city and county seat is Santa Rosa....

 in northwestern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. It is a highly variable tree, and closely related to Cupressus goveniana
Cupressus goveniana
Cupressus goveniana is a species of cypress endemic to coastal California in the United States, where it is found in small, scattered populations, not in large forests.-Description:...

,
enough to sometimes be considered a subspecies of it.

Description

The foliage is a dull dark to light green color, with scale-like leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

 1-1.5 mm long, with the leaf tips not spreading; seedlings bear needle-like leaves 8-10 mm long. The cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...

 are small, 11-24 mm long, and almost spherical, with six or eight scales arranged in opposite decussate pairs, with the bract visible as no more than a small lump or short spine on the scale. The seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

s are 3-5 mm long, with a pair of small wings along the sides. The cones remain closed on the trees for many years, until the trees are killed by a forest fire; after the tree is dead, the cones open to release the seeds which can then germinate successfully on the bare fire-cleared ground.

The Mendocino Cypress differs little from C. goveniana in morphology, with the most conspicuous difference in herbarium
Herbarium
In botany, a herbarium – sometimes known by the Anglicized term herbar – is a collection of preserved plant specimens. These specimens may be whole plants or plant parts: these will usually be in a dried form, mounted on a sheet, but depending upon the material may also be kept in...

 material being the usually glossy black seeds, unlike the dull brown seeds of C. goveniana, but even this character is not constant, with dull brown seeds found in the southernmost populations of C. pigmaea near Point Arena
Point Arena, California
Point Arena is a small coastal city in Mendocino County, California, United States. Point Arena is located west of Hopland, at an elevation of 118 feet . The population was 449 at the 2010 census, down from 474 at the 2000 census, making it one of the smallest incorporated cities in the state...

. Preliminary genetic studies have shown some differences, with notably some plastid
Plastid
Plastids are major organelles found in the cells of plants and algae. Plastids are the site of manufacture and storage of important chemical compounds used by the cell...

 sequences (matK, rbcL, and trnL) suggesting a possible closer relationship to C. macrocarpa
Cupressus macrocarpa
Cupressus macrocarpa, commonly known as Monterey Cypress or Macrocarpa, is a species of cypress that is endemic to the Central Coast of California. In the wild, the species is confined to two small populations, near Monterey and Carmel, California. These two small populations represent what was...

, though other sequences confirm its close relationship to C. goveniana. In cultivation together with C. goveniana, it retains a very different crown shape, with a tall slender crown, contrasting with the broad, shrubby crown of C. goveniana; it also has darker green foliage (paler, yellow-green in C. goveniana).

The largest recorded specimen is located in Mendocino County, with recorded dimensions of 43 m height, 2.13 m diameter, and 12 m crown spread, in 2000.

Taxonomy

Its taxonomic status is disputed by different authors. Some treat Cupressus pigmaea as a distinct species, following Sargent, including Wolf (1948), Griffin & Critchfield (1976), Lanner (1999), and Little et al. (2004), while others treat it within Cupressus goveniana
Cupressus goveniana
Cupressus goveniana is a species of cypress endemic to coastal California in the United States, where it is found in small, scattered populations, not in large forests.-Description:...

as either a variety
Variety (biology)
In botanical nomenclature, variety is a taxonomic rank below that of species: as such, it gets a three-part infraspecific name....

 (C. goveniana var. pigmaea Lemmon) or a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 (C. goveniana subsp. pigmaea (Lemmon) A.Camus), including Camus (1914), and the Jepson Manual (1993), and yet others do not distinguish it at all within C. goveniana, including the Flora of North America and Farjon (2005).

It has also more recently been transferred, along with the other New World Cupressus taxa, to the genus Callitropsis
Callitropsis
Callitropsis is a genus of cypresses in the family Cupressaceae, with several native to North America and one native to Vietnam in southeast Asia....

as Callitropsis pigmaea (Lemmon) D.P.Little by Little (2006).

The scientific name is sometimes spelled pygmaea, though this is an orthographic error.

Distribution and habitat

The Mendocino Cypress is highly variable in growth form, depending on soil conditions. In the pygmy forest
Pygmy forest
A pygmy forest is a forest which, for pedological and geological reasons, contains only miniature trees. Pygmy forests may occur over various world locations with notable occurrences being noted in the literature of the: California coastal terraces and inner coastal mountains of Northern...

 plant community on poor, acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

ic, nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...

-starved podsol
Podsol
In soil science, podzols are the typical soils of coniferous, or boreal forests. They are also the typical soils of eucalypt forests and heathlands in southern Australia...

 soils with drainage impeded by an iron hardpan
Hardpan
In soil science, agriculture and gardening, hardpan or ouklip is a general term for a dense layer of soil, usually found below the uppermost topsoil layer. There are different types of hardpan, all sharing the general characteristic of being a distinct soil layer that is largely impervious to water...

, it is a stunted tree from 0.2–5 meters in height at maturity. When occurring in its pygmy form, it is sometimes called Pygmy Cypress. When growing on deep, well-drained soils it can be a large tree up to 30–50 meters in height and 1–2.4 m in trunk diameter. The bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...

 is dark gray-brown, with stringy texture, and fissured on old trees.

Mendocino Cypress occurs in very limited ranges within only Mendocino County
Mendocino County, California
Mendocino County is a county located on the north coast of the U.S. state of California, north of the greater San Francisco Bay Area and west of the Central Valley. As of the 2010 census, the population was 87,841, up from 86,265 at the 2000 census...

, on some of the historical lands of the Yuki
Yuki tribe
The Yuki are a Native American people from the zone of Round Valley, in what today is part of the territory of Mendocino County, Northern California. Yuki tribes are thought to have settled as far south as Hood Mountain in present-day Sonoma County...

 Native American people. In Mendocino County the occurrence is in a discontinuous coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...

al terrace strip, primarily as a pygmy forest associated with Bishop Pine
Bishop Pine
The Bishop Pine, Pinus muricata, is a pine with a very restricted range: mostly in the U.S. state of California, including several offshore Channel Islands, and a few locations in Baja California, Mexico...

 (Pinus muricata) and Mendocino Shore Pine
Lodgepole Pine
Lodgepole Pine, Pinus contorta, also known as Shore Pine, is a common tree in western North America. Like all pines, it is evergreen.-Subspecies:...

 (P. contorta var. bolanderi). Occurrences are typically below 500 m in elevation. The Mendocino County official soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

s survey states that "While not formally recognized as a major forest cover type, the coastal portion of the survey area also includes Bishop Pine and Mendocino Cypress (pygmy) forest types".

Productivity

Along the Mendocino coastal terraces, whose geological age is approximately one million years, studies have been conducted of the biomass density and primary productivity of the Cupressus pigmaea-dominated pygmy forest. The terraces in this area extend a full five to ten kilometers inland from the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

.

In the Mendocino Cypress pygmy forests biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....

 was measured to range between 1.6 and 4.4 kilograms per square meter aboveground; moreover, net primary productivity was found to measure 180 to 360 grams per square meter per annum above the ground surface. Mean below-ground values are 3.5 kilograms biomass per square meter, productivity being 402 grams per meter per annum. The leaf-area ratio of the pygmy forest was estimated as 2.1 grams per square meter implying a high production efficiency per unit leaf area for an evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

 community (150 grams per meter aboveground ). According to Westman, productiviy of the C. pigmaea forest lie within the range expected for open, dry woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...

s. A similar community for which data is available is a pygmy conifer-oak scrubland in southern Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK