Common Beard Moss
Barbula unguiculata
Pottia mosses (Pottiaceae)
Description:
This acrocarpous moss forms clusters or mats of short plants about
0.5–2 cm. tall. The stems are more or less erect, unbranched,
terete, hairless (without fibrous rhizoids), and orange, red, or brown.
The leaves occur all
around each stem, becoming larger in size as they ascend upward. The
leaves are 1–2.5 mm. long, lanceolate-oblong to oblong in shape,
hairless, and
toothless along their down-turned margins; they are green to yellowish
green with well-defined midribs. The midribs extend along the entire
lengths of the leaves; they are slightly exserted at the leaf tips
(cuspidate). The lower sides of the leaves are slightly keeled along
the midribs. Under moist conditions, the leaves spread outward and they
may arch slightly. Under dry conditions, the leaves become somewhat
contorted and crinkled, becoming more appressed against the stems. The
cells of the leaves are quite small in size, hexagonal-shaped, and
minutely bumpy (multipapillose).
Because this moss is dioecious, male and female
reproductive organs occur on separate plants; these reproductive organs
are relatively inconspicuous. After fertilization occurs, sporophytes
develop consisting of spore-bearing capsules on a relatively long
stalks. The slender stalks (setae) are erect or ascending, straight or
somewhat crooked, 1–2.5 cm. long, terete, and hairless; they are
usually orange to red at maturity. At the apices of the stalks are more
or less erect spore-bearing capsules with membranous hoods. The capsule
bodies are nearly cylindrical in shape, but slightly broader at the
base than the apex; they are about 1.5 mm. long, tapered at the base,
and orange, red, or brown at maturity. The lids (opercula) of the
capsule bodies have long narrow beaks (about 1 mm. long) and they are
covered by membranous hoods (calyptra) that have even longer narrow
beaks (about 1.5 mm. long). The beaks of these hoods are often tilted
to one side. After the lids and hoods fall from the capsule
bodies, long teeth are revealed that are orange to red
and hair-like in appearance. These teeth spirally twist around each
other, or they may appear more spreading and frayed. Sometimes these
teeth are early-deciduous and they detach from the capsule bodies with
the lids.
The spores of the capsules are released
to the wind; this typically happens during late winter or spring. The
spores are globoid in shape and very small in size (about 10
micrometers across). The plants are anchored to the substrate by
fibrous rhizoids.
Cultivation:
The preference is partial sun to
moderate shade, moist to mesic conditions, and calcareous soil
containing
clay-loam or gravel. Most growth and development occurs during cool to
cold moist weather from autumn to spring, including above-freezing
winter days.
Range
& Habitat: Common Beard Moss (Barbula
unguiculata) is occasional to locally common in most areas of
Illinois,
although slightly more abundant in central and northern Illinois than
southern Illinois (see Distribution
Map). This moss is widely
distributed in the United States and Canada, and it also occurs in
Europe and other parts of the world. Common Beard Moss occurs in a wide
variety of habitats in Illinois, including ground soil in sandy
and non-sandy woodlands, shaded earthen banks, shallow soil of
limestone outcrops, soil-filled cavities of limestone boulders along
streams, sandy soil along streams, clay creek banks, gravelly ground
along roads, shaded ground soil along buildings, cemetery grounds, old
limestone quarries, soil-filled crevices of stone walls, soil-covered
concrete abutments of bridges, gravelly bottoms of roadside ditches,
burned ground of former campfire sites, mine spoils, dredge heaps from
rivers, and moist ground of open disturbed areas. While this moss
occurs sometimes in higher quality natural areas, it is more typical of
disturbed habitats, especially where soil-covered limestone or concrete
occurs.
Faunal
Associations:
Records of floral-faunal relationships for this moss in North America
have not been encountered, although the larvae of a moth, Catoptria
falsella, and a groundhopper, Tetrix ceperoi,
are known to feed on it in Europe.
Photographic
Location: On ground soil along the north side of
a building near shrubbery and a small tree in downtown Urbana,
Illinois. Close-up photos were taken with a microscope indoors.
Comments:
This is another obscure acrocarpous moss that can be found in a variety
of habitats. It can be distinguished from most mosses by the long
twisted hair-like teeth of its spore-bearing capsule bodies. These
spirally twisted teeth resemble either miniature tornadoes or messy
beards, and they probably
account for the common name, Beard Moss (from Barbula). However,
these teeth are also fragile and sometimes they fall off the capsule
bodies
rather easily.
Another moss species in this genus, Barbula
convoluta,
is rarely found in Illinois. It differs by having shorter leaves
(about 0.75–1.5 mm. long) that are more broadly oblong in shape and the
margins of its leaves curve downward only toward the leaf bases. Both
of these species have leaves that tend to taper abruptly to short
narrow tips, although the tips of Common Beard Moss (Barbula
unguiculata) are longer and more conspicuous. This moss also
resembles some of the Tornado
Mosses (Tortella spp.), especially Tortella
humilis (Small Tornado Moss).
Like Common Beard Moss, the spore-bearing capsules of Tornado Mosses
have
hair-like teeth that are spirally twisted, resembling miniature
tornadoes. Small Tornado Moss differs from Common Beard Moss in having
slightly longer leaves (2–3.5 mm. long) that taper more gradually
toward their tips. The margins of these leaves are relatively flat,
while the leaf margins of Common Beard Moss are down-turned. Under dry
conditions, the leaves of Common Beard Moss are held erect, but
they are also rather crisped and contorted in appearance. In contrast,
the dry leaves of Small Tornado Moss (and other Tornado mosses) fold
inward along their midribs and then curl, looking like miniature
curved ropes. Another common name of Barbula unguiculata is
Bird's Claw Beard Moss.