Meesia triquetra
Encyclopedia
Threeranked humpmoss is a moss that occurs all around the northern hemisphere
in higher latitude
s.
s, often large, are acrocarpous and dioicous. In color they are dark-green to grass-green above, occasionally red-brown below due to dense rhizoids. The plant's stem
s are not branched or little branched, pale-brown to yellow-brown, closely foliate, and 2–14 cm high. Its leaves
are decurrent, squarrose (spreading) when moist, triangular to ovate to lanceolate, somewhat crispate (contorted), 2–3½ mm long, and tristichous (in three obvious ranks). The leaf margins are sharply serrate or denticulate to the base or nearly so, plane or sometimes recurved in the middle of the leaf. The costa is relatively narrow (less than 1/5 the width of the leaf base), subpercurrent to percurrent, gradually tapering at distal end. The leaf's apex is acute to acuminate (sharply pointed). The lamina is unistratose throughout. Meesia triqueta's perigonia are terminal in discoid heads. The seta is straight and smooth, brown to yellow-brown, and very long (4–10 cm). The capsule is asymmetrical, somewhat pyriform, 2¾–5½ mm long including the neck; the hypophysis (neck) is long (comprising up to ½ of capsule length), moderately well-defined, not much wrinkled when dry; the urn is oblong to short-cylindric, arcuate and asymmetric, brown to yellow-brown, up to 4 mm long, and when dry, wrinkled but not regularly sulcate. The operculum is short-conic; the endostome cilia are often rather well-developed. The plant's spore
s are finely papillose.
, northern Asia
, Greenland
, Canada
, and the northern U.S. Some discoveries have been reported from Oceania
.
These moss
es occur in wetland
sites, specifically, within wet woods in the wettest portions of what are called "extreme rich fen
s" (i.e., fens having surface waters with high pH
and calcium
concentrations). Montagnes describes this species as a "rich fen indicator of high fidelity." Associates include Scorpidium spp. and Drepanocladus revolvens.
The fire ecology
of this plant is not known; however, fen
s rarely burn. Excess soot from a nearby fire, however, might negatively affect habitat
quality. Fire return intervals in conifer bog
s, a somewhat similar mire
-type habitat
, are estimated to be about once every 150-200 years. Fire
does significant damage to peat, but the bog must be dry (as during a drought
year) in order to burn; typically, bogs are not dry enough.
Pacific Southwest Region Sensitive Species.
California Native Plant Society
List 4.2
NatureServe
California State Rank: S2.2; Global Rank: G5
Fens are delicate habitat
s susceptible to impacts from livestock
grazing
, hydrologic alteration, construction and continued use of roads, and peat
mining. Rich fen habitats are especially susceptible to modification. The surface water chemistry of rich fens is sensitive to climatic and anthropogenic influences. This species has reached near extinction
in Europe.
by its squarrose leaves; narrow costa relative to the size of the leaf base; serrate, planar leaf margins; and acute leaf tips. In contrast, M. uliginosa a wide (up to 1/3 of the leaf base) costa, entire, revolute leaf margins, and blunt apices. Other Meesia species also have blunt apices..
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
in higher latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
s.
Technical description
Meesia triqueta grows in small tufts or cushions. The plantPlant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
s, often large, are acrocarpous and dioicous. In color they are dark-green to grass-green above, occasionally red-brown below due to dense rhizoids. The plant's stem
Plant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...
s are not branched or little branched, pale-brown to yellow-brown, closely foliate, and 2–14 cm high. Its 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....
are decurrent, squarrose (spreading) when moist, triangular to ovate to lanceolate, somewhat crispate (contorted), 2–3½ mm long, and tristichous (in three obvious ranks). The leaf margins are sharply serrate or denticulate to the base or nearly so, plane or sometimes recurved in the middle of the leaf. The costa is relatively narrow (less than 1/5 the width of the leaf base), subpercurrent to percurrent, gradually tapering at distal end. The leaf's apex is acute to acuminate (sharply pointed). The lamina is unistratose throughout. Meesia triqueta's perigonia are terminal in discoid heads. The seta is straight and smooth, brown to yellow-brown, and very long (4–10 cm). The capsule is asymmetrical, somewhat pyriform, 2¾–5½ mm long including the neck; the hypophysis (neck) is long (comprising up to ½ of capsule length), moderately well-defined, not much wrinkled when dry; the urn is oblong to short-cylindric, arcuate and asymmetric, brown to yellow-brown, up to 4 mm long, and when dry, wrinkled but not regularly sulcate. The operculum is short-conic; the endostome cilia are often rather well-developed. The plant's spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s are finely papillose.
Distribution, habitat, and ecology
This species has a circumboreal distribution: it is found in Northern EuropeNorthern Europe
Northern Europe is the northern part or region of Europe. Northern Europe typically refers to the seven countries in the northern part of the European subcontinent which includes Denmark, Estonia, Latvia, Lithuania, Norway, Finland and Sweden...
, northern Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, and the northern U.S. Some discoveries have been reported from Oceania
Oceania
Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...
.
These moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
es occur in wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
sites, specifically, within wet woods in the wettest portions of what are called "extreme rich fen
Fen
A fen is a type of wetland fed by mineral-rich surface water or groundwater. Fens are characterised by their water chemistry, which is neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients...
s" (i.e., fens having surface waters with high pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
and calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
concentrations). Montagnes describes this species as a "rich fen indicator of high fidelity." Associates include Scorpidium spp. and Drepanocladus revolvens.
The fire ecology
Fire ecology
Fire ecology is concerned with the processes linking the natural incidence of fire in an ecosystem and the ecological effects of this fire. Many ecosystems, such as the North American prairie and chaparral ecosystems, and the South African savanna, have evolved with fire as a natural and necessary...
of this plant is not known; however, fen
Fen
A fen is a type of wetland fed by mineral-rich surface water or groundwater. Fens are characterised by their water chemistry, which is neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients...
s rarely burn. Excess soot from a nearby fire, however, might negatively affect habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
quality. Fire return intervals in conifer bog
Bog
A bog, quagmire or mire is a wetland that accumulates acidic peat, a deposit of dead plant material—often mosses or, in Arctic climates, lichens....
s, a somewhat similar mire
Miré
Miré is a commune in the Maine-et-Loire department in western France....
-type habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
, are estimated to be about once every 150-200 years. Fire
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....
does significant damage to peat, but the bog must be dry (as during a drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
year) in order to burn; typically, bogs are not dry enough.
Conservation status and threats
U.S. Forest ServiceUnited States Forest Service
The United States Forest Service is an agency of the United States Department of Agriculture that administers the nation's 155 national forests and 20 national grasslands, which encompass...
Pacific Southwest Region Sensitive Species.
California Native Plant Society
California Native Plant Society
The California Native Plant Society is a California not-for-profit organization that seeks to increase understanding of California's native flora and to preserve that flora. Its "paramount purpose is to preserve wild plants".-History:...
List 4.2
NatureServe
NatureServe
NatureServe is a non-profit conservation organization whose mission is to provide the scientific basis for effective conservation action. NatureServe and its network of natural heritage programs are the leading source for information about rare and endangered species and threatened ecosystems in...
California State Rank: S2.2; Global Rank: G5
Fens are delicate habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s susceptible to impacts from livestock
Livestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
, hydrologic alteration, construction and continued use of roads, and peat
Peat
Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...
mining. Rich fen habitats are especially susceptible to modification. The surface water chemistry of rich fens is sensitive to climatic and anthropogenic influences. This species has reached near extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
in Europe.
Field identification
M. triquetra is easily recognized by its distinct three-ranked leaf arrangement and for being dioicous. It may be distinguished from M. uliginosaMeesia uliginosa
Broadnerved humpmoss , is a rare moss of the Western U.S. It occurs all around the northern hemisphere in higher latitudes, and in some places is not as rare as in the Western U.S.- Technical description :...
by its squarrose leaves; narrow costa relative to the size of the leaf base; serrate, planar leaf margins; and acute leaf tips. In contrast, M. uliginosa a wide (up to 1/3 of the leaf base) costa, entire, revolute leaf margins, and blunt apices. Other Meesia species also have blunt apices..