Graceful Chain Moss
Leskea gracilescens
Chain Moss family (Leskeaceae)
Description:
This perennial evergreen moss forms a low mat of branching leafy stems;
its foliage is dark green or brownish green and hairless. The terete
stems and their branches are straight or crooked; they are mostly
covered on all sides by
overlapping leaves. When the foliage of this moss is moist, the leaves
are ascending-spreading, forming about a 45–60° angle with the stems.
When
the foliage is dry, the leaves are erect-appressed along the stems,
causing this moss to appear stringy. The leaves of stems are
0.6–0.8 mm. long, ovate in shape, and toothless (entire) along their
margins. The leaves of branches are similar, except they are
only 0.4-0.5 mm. long. Leaf tips are acute, while leaf bases clasp
their stems. The leaves are convex along their outer surface and
concave along their inner surface; their margins are rolled under
(revolute). Leaves that become dry may form a pair of pleats that
extend along both sides of the central vein (one pleat on each side);
these longitudinal pleats extend along the lower one-third of their
leaves.
When they are viewed under magnification, the bulging leaf cells are
small in size throughout, forming circular, squarish, or irregularly
polygonal shapes.
Spore-bearing capsules on slender stalks are produced
once a year, usually during the spring. The stalks (setae) are 5-10 mm.
long, light yellowish brown to dull red, terete, smooth, and more or
less erect (relative to the orientation of the matted moss). The
spore-bearing capsules are 1.5–2.5 mm. long and straight-cylindrical in
shape; relative to their stalks, they are erect. They
are light green while immature, becoming brown with age. The lid
(operculum) at the apex of each capsule has a medium-conical shape; the
lid and upper capsule are covered with a hairless membranous hood
during an early stage of development; this hood has a long-conical
beak. Eventually, the lid of each capsule falls off to release the tiny
spores to the wind. Individual spores are 10-15 microns across, globoid
in shape, and finely warty or bumpy. The teeth of the capsule are
revealed after
the lid falls off; they are relatively long (about 0.3 mm.), yellowish
brown, narrowly triangular, slightly incurved, and arranged in pairs.
This moss has fibrous rhizoids that enable it to cling to coarse
surfaces.
Cultivation:
The preference is light to deep shade, moist humid
conditions, tree bark surfaces, and protection from prevailing winds.
During hot dry periods with low humidity, this moss becomes dormant,
but it
resumes growth when cool temperatures, moisture and humidity return.
There is some
tolerance to urban and suburban air pollution if it is not too severe.
Range
& Habitat: Graceful Chain Moss (Leskea
gracilescens) is occasional
to common throughout Illinois (see Distribution
Map).
It may occur in
every county of the state. Outside of the state, this moss is widely
distributed in eastern North America. Habitats include lower trunk bark
of trees in woods and wooded ravines, bark of fallen trees
in woods and ravines, rotting tree stumps in woods and other shaded
areas,
lower trunk bark of trees in swamps, bark of fallen trees in
swamps, rotting tree stumps in swamps, lower trunk bark of trees
in parks and picnic areas, lower trunk bark of trees at
farmhouses, lower trunk bark of trees in urban and suburban
residential areas, lower trunk bark of trees along roadsides, lower
trunk bark of trees along rivers, bark of fallen trees along
rivers, exposed roots of trees in various shaded habitats, shaded areas
of asphalt and shingle roofs, and on rocks along spring runs in moist
shaded
areas.
The trees of these habitats are usually living, although sometimes
they are dead. In Illinois, this moss has been found on such hardwood
trees as
ash, elm, hawthorn, pecan, willow oak, maple, hackberry and cottonwood.
It also occurs on the trunk and branches of Eastern Red Cedar
(Juniperus virginianus). This moss is somewhat
weedy, often occurring
in disturbed habitats, but it is also found in high quality natural
areas.
Faunal
Associations: This moss has been used as nesting
material by the Carolina Chickadee (Andreas, 2010). This bird often
selects mosses that grow on trees for this purpose as it rarely lands
on the ground.
Photographic
Location: Chief Shemauger Park and Busey Woods
in Urbana, Illinois. Close-up photos were taken indoors with a
microscope.
Comments:
This is one of the most common mosses to be found on the bark of trees
in Illinois. It often occurs on trees in residential areas. Graceful
Chain Moss (Leskea gracilescens)
has a
stringy unattractive appearance when it is dry, but this moss becomes
more luxuriant in appearance after significant rainfall. Other Chain
Mosses (Leskea spp.) are less common in Illinois.
One of
them, Obtuse Chain Moss (Leskea obscura), is very
similar in appearance,
except its leaves have blunt tips and its spore capsules are slightly
shorter and their conical lids are more short and blunt. Another
species, Curved Chain Moss (Leskea polycarpa), has
light green foliage,
instead of dark green foliage, and its leaf tips are conspicuously
curved in one direction. Another species, Southern Chain Moss (Leskea
australis) which is restricted to the southern tip of
Illinois, has
even smaller leaves and shorter capsules. All of these species prefer
to grow on trunk bark of hardwood trees. Other common names of Leskea
gracilescens are Leskea Moss and Necklace Chain Moss.