Pleated Foxtail Moss
Foxtail Mosses (Brachytheciaceae)
This pleurocarpous moss forms low mats of branching leafy stems on the
ground; the branching pattern of this moss is somewhat erratic.
Depending on environmental conditions, the stems and leaves are light
green, light golden yellow, or yellowish brown; the tips of young
leafy stems are whitish, terete (not compressed), and sword-like. The
leaves tend to hug their stems and become longitudinally pleated when
they are dry, but they spread away from the stems at about a 45° angle
and become less pleated when they are wet. The overlapping leaves are
arranged in moderately dense spirals along their stems. Both the stems
are hairless. The leaves along primary stems are 1.5–2 mm. long and
ovate in shape, while the leaves along secondary stems are 1–1.5 mm.
long and ovate to ovate-lanceolate in shape. The leaves are finely
serrated along the entire length, or along the outer one-half, of their
margins (requires magnification to see); their margins do not have a
clear border. The leaves are somewhat convex along their outer sides
and concave along their inner sides. They have solitary midribs that
extend to about two-thirds or three-fourths of their length. One to two
pairs of longitudinal pleats often extend along both sides of the
midrib. The leaf bases strongly clasp their stems, while the leaf tips
are long and slender.
The cells of the leaves are narrow and elongated
toward their tips, but they become more angular toward their bases.
This moss is usually dioicous with separate male and female plants.
During the spring, and possibly other times of the year, female plants
produce sporophytes (spore-bearing capsules with stalks) at intervals
along their stems. The slender stalks (setae) are 8-25 mm. long,
ascending to erect, terete, hairless, smooth-textured, and reddish
yellow, orange, or reddish brown when they become mature. The body of
each spore-bearing capsule is 2-3 mm. long, arching-cylindrical in
shape, and tapered at the base. The bodies of immature capsules are
light green, but they soon become reddish yellow, orange, or reddish
brown as they become more mature. The lids (opercula) of these capsules
are conical in shape with nipple-like tips; they are late-deciduous.
Both the lids and upper bodies of immature capsules are covered with
membranous hoods (calyptrae) that are early-deciduous. When the lid of
a capsule falls off, a ring of incurved teeth is revealed. These teeth
are linear-lanceolate in shape with bifurcated tips; they are yellow,
orange, or red, but later become more brown like the capsules.
Mature capsules are somewhat constricted below their ring of teeth.
tiny spores are released during the late spring or summer (and possibly
other times of the year); they are distributed by the wind. Individual
spores are about 15 micrometers across, globoid in shape, and finely
warty or bumpy (papillose). The stems of very young plants are anchored
to the ground with fibrous rhizoids, but most stems of more mature
plants lack rhizoids altogether. Clonal offsets of this moss are
sometimes produced when the stems break away from the mother plant as a
result of disturbance or the withering away of old stems.
The preference is light shade to partial sun, moist to dry-mesic
conditions, and soil containing loam, clay-loam, or clay. This moss
also adapts to rocky ground, moist rocks, rotting logs, and the bases
of trees. It is rather common and weedy.
The native Pleated Foxtail Moss (Brachythecium laetum)
throughout Illinois (see Distribution
Map). It probably occurs in every
county of the state. This moss is widely distributed in the eastern
half of the United States and southern Canada. It also occurs in parts
of southwestern United States and Mexico. Habitats include ground soil
in woodlands, north-facing wooded slopes, ground soil in wooded bluffs,
ground soil in open woodlands, ground soil in swampy woodlands, slopes
of ravines in wooded areas, rotting logs in ravines and wooded areas,
rotting logs in swamps, bases of old trees, shaded earthen banks, clay
banks along streams and creeks, slopes along rivers, roadside
embankments, shaded areas along roads, shaded damp areas along
limestone and sandstone cliffs, moist rocks of algific limestone talus,
borders of limestone sinks, moist rocks in ravines and wooded areas,
cave walls near their entrances, abandoned limestone quarries, shaded
rooftops of buildings, shrubby fallow fields, disturbed ground of
cemeteries with groves of trees, disturbed ground in city parks, and
disturbed areas of shaded lawns. The preceding wooded habitats are
dominated by various deciduous trees, especially oak and maple. This
moss is common in many disturbed areas, although it also occurs in high
quality natural areas.
Many songbirds use
this mat-forming moss in the construction of their nests. This includes
the Barn Swallow, Carolina Wren, Catbird, Eastern Phoebe, American
Robin, Least Flycatcher, Rufous-sided Towhee, and Slate-colored Junco
(Breil & Moyle, 1976).
Location: A semi-shaded disturbed ground of
Crystal Lake Park in Urbana,
Illinois. Close-up photographs were taken with a microscope indoors.
Foxtail mosses (Brachythecium spp.) are difficult to
each other and their taxonomic history has been somewhat unstable.
Following the guidance of efloras, this moss has been assigned the
scientific name, Brachythecium laetum. Under this
taxonomy, both Brachythecium oxycladon and Brachythecium
digastrum are considered
scientific synonyms of this species. Of these latter two names, Brachythecium
oxycladon is still widely used as the scientific name of this
is relatively easy to confuse this moss with another species that is
common and weedy, Brachythecium salebrosum (Golden
Foxtail Moss). This
latter moss has leaves that are more narrow in shape (lanceolate-ovate
to lanceolate) and slightly longer (2–2.5 mm. for leaves of primary
stems, 1.5–2 mm. for leaves of secondary stems). The spore-bearing
capsules of this moss are also slightly shorter in length (typically
about 2 mm. in length). There are several other species of Foxtail Moss
that occur in Illinois, but they are less common and more distinct in
appearance. Another common name of Brachythecium laetum
Foxtail Moss, although this name also refers to Brachythecium
salebrosum. If it receives any exposure from the sun, Pleated
Moss (Brachythecium laetum) has attractive golden
yellow foliage during
the spring, but it has a tendency to fade away and turn brown during
hot summer weather.