White-tipped Moss family (Hedwigiaceae)
This evergreen perennial moss forms a low cushion of plants up to 1"
(2.5 cm.) tall and up to 1' (30 cm.) or more across. While this looks
like a pleurocarpous moss, it is actually an acrocarpic moss with a
pseudo-pleurocarpous habit of growth (De Luna, 1990). Individual stems
are red to brown, terete, and largely devoid of hair-like rhizoids;
widely spreading, ascending, or erect. Dichotomous branching of the
stems usually occurs after the production of terminal reproductive
Leaves occur all around and along the stems, and their distribution is
moderately dense. Individual leaves are 1.5–2 mm. long,
shape, and toothless along their margins; they strongly clasp the stems
at their bases, while their tips are narrowly acute, sometimes tapering
into awn-like bristles. The leaves are concave-convex and
slightly to moderately
recurved; sometimes their tips are slightly incurved. The lower leaf
margins are moderately
revolute (rolled downward), while their middle to upper margins
are slightly revolute to flat. When they are moist, the leaves spread
away from their stems by a 45°–75° angle, while dry leaves are erect or
appressed along their stems. The leaves are predominately green or
yellowish green when they are moist, becoming more grayish green and
pale when they are dry. The tips of the leaves (including their
bristles, if any) are translucent-white from a lack of chlorophyll;
this translucent-white region may extend to the outer one-third of the
leaves. As the leaves become old and withered, they become completely
translucent-white before detaching from their stems. Leaf cells are
shaped like short irregular rectangles for the most part; they appear
minutely bumpy (papillose) under the microscope.
This moss is
monoicous, producing male reproductive organs (antheridia) and female
reproductive organs (archegonia) at the tips of different branches on
plant during the spring. After the sperm have fertilized the ovae,
develop that are nearly sessile. The capsule bodies with their
lids (opercula) are about 1.5 mm. in diameter, ovoid-globoid in shape,
and pale brown to reddish brown when they are mature. The lids are very
shallow; they are flat on the bottom, and low convex-conical above.
White-membranous hoods (calyptrae) cover the capsule bodies and their
lids initially, but they soon split apart and fall to the ground.
Eventually, the lids detach from their capsules, releasing the spores
the wind. There are no rings of teeth surrounding the openings of the
capsules. Individual spores are 20-30 micrometers across,
globoid-angular in shape, and minutely bumpy (papillose). Individual
plants become attached to the substrate when their stem bases and lower
stems develop fibrous rhizoids. Asexual reproduction is
possible when fragments of leafy stems, resulting from some kind of
disturbance, develop new fibrous rhizoids that attach themselves to the
The preference is full sun to light
shade, moist to dry conditions, and acidic rocks or rocky material for
a substrate. However, this moss can also tolerate limestone or dolomite
with a higher pH. It can also adapt to such surfaces as roofing
material, barren soil, and logs. This moss is more tolerant of sunlight
and dry conditions than most moss species, making it a good candidate
for rock gardens and green rooftop gardens.
& Habitat: The native White-tipped Moss (Hedwigia
occasional in NE Illinois, east-central Illinois, and southern
Illinois, while in the rest of the state it is uncommon or absent (see Distribution
This moss is widely distributed throughout the
world, including North America, South America, Eurasia, Africa, and
Australia. In Illinois, habitats include sandstone walls in canyons,
sandstone bluffs and rocky ridges, faces of limestone rocks, steep
slopes of ravines in woodlands, rocks and boulders along woodland
trails, rocks and boulders along woodland streams and springs, steep
banks along creeks, rocks along ponds, pockets of sandy clay on
sandstone outcrops, sandstone glades, exposed rocky hills, old stone
walls of churches and other property, areas along the foundations of
buildings, old shingle roofs on cabins, and asphalt roofs on buildings.
Outside of the state, this moss has been found on the lower trunks of
trees. In general, this moss prefers to grow on acidic rocks in either
upland open woodlands or inside canyons, but it also grows on hard
grainy surfaces in urban and residential areas.
Associations: The Barn Swallow, American Robin,
Dark-eyed Junco, and other songbirds occasionally use fragments of this
moss in the construction of their nests (Breil & Moyle, 1976).
Location: Indoors using nursery-cultivated
plants. Close-up photos were taken with a microscope.
White-tipped Moss (Hedwigia ciliata)
is variable in appearance
depending on the amount of translucent whiteness toward the tips of its
leaves and whether or not conspicuous white bristles occur at the tips
of its leaves. Generally, specimens of this moss in eastern North
America have leaves with only a small region of translucent whiteness
at their leaf tips with little or no bristles. As the leaves age,
however, they become more white-translucent before withering away.
White-tipped Moss can be distinguished from other similar mosses by its
white-tipped and sometimes bristly leaves, the absence of midribs on
its leaves, the revolute margins on its leaves (at least along their
lower margins), the minute bumpiness of its leaf cells, and its sessile
or nearly sessile globoid spore-capsules. Also, unlike many mosses,
White-tipped Moss prefers to grow on relatively dry and exposed rocks,
even rooftops. Other common names of this moss include Fringed Hoar
Moss, Ciliate Hedwigia Moss, Hedwig's Fringeleaf Moss, and Medusa Moss.
There are no other moss species in the Hedwigia genus in Illinois.