Umbrella Liverwort family
This non-vascular evergreen plant consists of a dichotomously branched
(undifferentiated plant body) that spans 2–8 cm. long, 1-8 cm. across,
and up to 1.5 mm. in thickness. It is prostrate on the ground,
clambering over adjacent thalli. Individual lobes of the thallus are
8-15 mm. across, however adjacent lobes have a tendency to merge
together at their bases. The thallus becomes thinner toward its
margins. These margins
are smooth, undulate, and toothless overall; the tips of the lobes
are notched. The upper surface of the thallus is bright green
and glabrous, although it may turn pale purple with age along the
the slightly thickened middle of the lobes, the thallus has
disconnected lines of black. The upper surface of the thallus is
faintly indented into small
linear-rectangular, rectangular, or rhombic sections; each section has
a small white air chamber with a single barrel-shaped pore. These tiny
remain open (requires 10x magnification or more to see).
along the middle of each lobe on the upper surface the thallus, there
are solitary gemma cups. These gemma cups have circular membranous rims
that are crenate along
their upper margins; each gemma cup is shaped like a shallow circular
pan. A few gemmae (asexual plant buds) develop within each cup.
Individual gemmae are about 1 mm. across, green, and more or less ovoid
in shape. At maturity, they are distributed to new locations by
raindrop logistics or the movement of water. After leaving the mother
plant, each gemma can form 1-2 clonal plants after establishing contact
with moist ground. This liverwort is dioecious, forming male
reproductive organs and female reproductive organs on separate plants.
On mature male plants, antheridiophores (stalked receptacles with male
reproductive organs) develop from the thallus lobes;
they are 1-3 cm. tall. These antheridiophores resemble flattened
umbrellas in overall form, consisting of 6-8 spore-bearing lobes that
radiate outward from the apex of a naked stalk. The spore-bearing lobes
are elliptic-oblong in shape, grayish green or purplish
green, warty, glabrous, and interconnected by a translucent membrane
margins. The stalk of
the antheridiophore is light green to purplish green, terete, and
maturity, the antheridiophores release their spores from the upper side
of the spore-bearing lobes.
On mature female plants, archegoniophores
(stalked receptacles with female reproductive organs) also develop from
thallus lobes; they are 4-6.5 cm. tall. These
archegoniophores resemble palm trees with narrow drooping fronds in
form, consisting of 8-11 ovary-bearing lobes that radiate outward and
downward from the apex of a naked stalk. The ovary-bearing lobes are
oblong in shape and green above with down-curved margins; the ovaries
are attached to the undersides of these lobes. The stalk of the
archegoniophore is light green to purplish green, terete, and glabrous.
sperm from male plants reach the ovaries of female plants by splashing
raindrops, capillary action of water, and swimming. Along the
underside of the thallus, there are scales and two types of rhizoids.
The scales are arranged in 3 rows on each side of the thallus. Long
wiry rhizoids anchor the thallus to the substrate and hold it in place,
while short peg-like rhizoids absorb water from the substrate to keep
thallus hydrated. Quite often, clonal colonies of plants are produced
from the gemmae.
The preference is partial sun to medium shade, consistently moist or
intermittently wet conditions, and erosion-resistant ground containing
clay or some other material. This plant can tolerate occasional floods
if they are temporary. Sometimes it invades greenhouses, where it can
become a pest.
& Habitat: Umbrella Liverwort (Marchantia
is occasional to fairly common throughout Illinois, where it is native
Map). This plant is widely distributed in North America and
other continents around the world. In Illinois, habitats include wet
areas of north-facing limestone and sandstone cliffs, mud at entrances
to caves, north-facing banks of creeks, shaded rocks along streams, wet
depressions in woods, sandy ground underneath rocky overhangs in
canyons, wet ground on algific limestone talus, bottoms of shaded
ravines, sandy soil along rivers, drier areas of peat bogs, hillside
seeps, cattail-dominated swales, shaded walls of jails and other old
buildings, shaded ground along the foundations of large buildings,
burned-out mine dumps, poorly drained areas of fields, and greenhouses.
This liverwort has a tendency to occur in disturbed wetland areas,
although it also occurs in higher quality natural areas.
Associations: Information about floral-faunal
relationships for this plant are unavailable at the present time.
Location: A north-facing bank of a creek in
Umbrella Liverwort (Marchantia polymorpha)
is a plant that looks like it came from another
planet. However, liverworts are among the oldest terrestrial
plants on Earth. This is the only liverwort in Illinois that has both
male and female reproductive structures on stalked receptacles
(archegoniophores and antheridiophores). It is also the only liverwort
that has fringed circular gemma cups on the upper surface of the
thallus. Like other thalloid liverworts, Umbrella Liverwort lacks true
leaves and stems. Instead, the gametophytic body of this liverwort
consists of a flat green thallus that is capable of photosynthesis.
similar species, Marchantia aquatica (Water
Liverwort), is much
less common. It differs from Umbrella Liverwort by having continuous
black lines along the middle of the lobes of its thallus. It is found
in high quality wetlands, rather than disturbed areas. Another
similar species, Marchantia alpestris (Mountain
Liverwort), has not been found in Illinois. It differs from Umbrella
Liverwort by having a yellowish green thallus that lacks black
lines, whether continuous or discontinuous, along the middle of
its lobes. Not surprisingly, this liverwort is found in alpine habitats
on mountains. Sometimes, these 3 thalloid liverworts are treated as
subspecies of the same species, in which case Umbrella Liverwort is
referred to as Marchantia polymorpha ruderalis.
Another common name of this plant is Common Liverwort.