''Plagiomnium cuspidatum'', also known as toothed or “baby-tooth” ''plagiomnium'' moss and woodsy thyme-moss, is a species of thyme-moss that originated in North America, but can now also be found throughout Middle America, Africa, Northern and Southern Asia (excluding China), and Europe.
''Plagiomnium cuspidatum'' can commonly be found growing along the base of trees, stumps, coarse woody debris, and rocks in base-rich habitats such as:
wet meadow
A wet meadow is a type of wetland with soils that are Solubility, saturated for part or all of the growing season which prevents the growth of trees and brush. Debate exists whether a wet meadow is a type of marsh or a completely separate type of ...
s, forested rich peatlands, wet forests, fire-dependent woodlands, mesic hardwood forests, and cliff/talus at low to moderate elevations.
It is commonly used by songbirds and salamanders for nesting material in the wild, and by humans as planting material in bioactive terrariums, aquariums, and paludariums due to their anti- microbial and antifungal properties.
These properties are also being researched for more medicinal uses.
Description
Leaves
''Plagiomnium cuspidatum'' has sharp-toothed leaf margins, as its common names suggest, and can be identified from other members of the ''Plagiomnium'' genus by their leaves which measure to about 2.5–3.5 mm in length and have a tip that is tapered more gradually than other ''Plagiomnium'' species, a leaf base that runs all the way down onto the stem, and leaf cells that are elongated and clearly not arranged in diagonal rows.
''P. cuspidatum'' is often characterized as a small moss with shoots ranging from 1.5-4 cm tall and leaves roughly around 3 mm long.
Leaves of ''P. cuspidatum'' gradually taper towards the tip, more so than other species in the genus.
Leaf margins are sharply toothed and are absent in the lower half of the leaves while the midrib is obvious.
Leaves are arranged in pseudo whorls- where the arrangement of leaves appear to originate at the same level but do not.

Using a x20 hand lens, the small cells can be seen to not be in diagonal rows and no longer than wide.
The non-fertile stems can be one of two descriptions: erect or curved. When aggregated together, the plant forms a green cushion-like structure. When dry, the leaves darken and begin to curl.
Reproductive structures
''Plagiomnium cuspidatum'' do not reproduce asexually but are dioicous – having antheridia and archegonia on separate plants – and synoicous- having archegonia and antheridia on the same plant.
From the foot of the plant, there can be multiple seta that raises the capsules above the plant. Capsules are frequent have a conical lid. Spores range from 18-40μm and are numerous inside the capsule.
Distribution
''Plagiomnium cuspidatum'' originated in North America, but can now also be found throughout Middle America, Africa, Northern and Southern Asia (excluding China), and Europe. It is widely distributed throughout North America and Europe, but is less commonly found in Africa and Eastern Asia.
Throughout North America, it can be predominantly found in the warmer, humid areas of the continent, though it can still be found and survive in more cooler climates as well.
''Plagiomnium cuspidatum'' is known to be able to use
artificial light
Lighting or illumination is the deliberate use of light to achieve practical or aesthetic effects. Lighting includes the use of both artificial light sources like lamps and light fixtures, as well as natural illumination by capturing daylight. ...
to grow in places which are otherwise devoid of natural light, such as
Crystal Cave in
Wisconsin
Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...
.
Ecology
Within North America and Europe, ''P. cuspidatum'' is often found growing along the base of trees, stumps, coarse woody debris, and rocks in base-rich habitats such as:
wet meadow
A wet meadow is a type of wetland with soils that are Solubility, saturated for part or all of the growing season which prevents the growth of trees and brush. Debate exists whether a wet meadow is a type of marsh or a completely separate type of ...
s, forested rich peatlands, wet forests, fire-dependent woodlands, mesic hardwood forests, and cliff/talus at low to moderate elevations.
The moss is often used by songbirds to make the inner lining of their nest and by
four-toed salamanders (''Hemidactylium scutatum'') when nesting to prevent movement of their eggs.
Located at the bottom of the mosses, the rhizomes are used by the salamanders to attach their eggs to, which aids in stabilization.
Uses
Cultivation
It can be used as a planting medium in
bioactive terrariums, aquariums, and paludariums too due to its anti-microbial and antifungal properties.
Its ability to retain high humidity levels and grow in mats or carpets, which provides great cover for the tank's "
clean-up crew
The clean-up crew is the term that has been used by many aquarists and vendors since the late 1980s to refer to various small animals commonly sold for use in keeping the reef aquarium clear of pest algae, detritus and parasites.
Among the most ...
", also make it perfect for the hobby.
Medicinal
In many bryophytes, there have been antibacterial, antiviral, and antioxidant properties associated with certain species.
''P. cuspidatum'' is able to produce substances that can inhibit bacteria and fungi. But due to these substances being unstable, they have not been able to be used in the medical field but have garnered some attention for its potential use.
The instability of the substance stems from the substance being produced while the moss is under stress and a variety of species produce a variety of substances.
It has been seen that ''P. cuspidatum'' showes resistance to methicillin-resistant ''
Staphylococcus aureus
''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posi ...
,'' commonly known as MRSA.
Also, the extracts of ''P. cuspidatum'' studied have shown promising antiproliferative activities against cancer cell lines in which 50% inhibition or more was achieved when testing on cervical, ovarian, and breast cancer cell lines.
The extracts of ''P. cuspidatum,'' flavonoids, have been a topic of interest. Flavonoids are polyphenolic secondary metabolites that are commonly consumed in human diets.
A few of the major flavonoids of ''P. cuspidatum'' are
saponarin
Saponarin is a flavone glucoside. It is found in '' Saponaria officinalis'' and in ''Strongylodon macrobotrys'' where it imparts the characteristic jade color to the flower. This coloration has been shown to be an example of copigmentation, a resu ...
e,
luteolin
Luteolin is a flavone, a type of flavonoid, with a yellow crystalline appearance.
Luteolin is the main yellow dye from the '' Reseda luteola'' plant, used for dyeing since at least the first millennium B.C. Luteolin was first isolated in pure f ...
, and
apigenin-7''-O''-neohesperidoside.
References
{{Taxonbar, from=Q292398
Mniaceae