Lizard Crystalwort
Riccia bifurca
Crystalwort family (Ricciaceae)
Description:
This thalloid liverwort is usually an
annual that matures during late autumn, although in wet places with
mild winters it may become semi-perennial and survive several years.
The thallus (undifferentiated body) of this plant is dichotomously
branched into lobes 1-5 times, forming a pseudo-rosette or overlapping
mat of lobes
up to 20 mm. across (rarely more). The mature lobes of a thallus are
about 1–1.5 mm.
across, 4–6.5 mm. long, and tongue-shaped, although the tips of the
lobes are slightly
notched. The margins of the thallus are somewhat swollen,
extending farthest from the bottom. Except for the unbranched
basal portion of the thallus, its upper surface and branched lobes have
central longitudinal grooves. These
grooves can extend up to one-third across the diameter of the lobes
and the bottoms of these grooves are flat or gently rounded. Toward the
tips of the
lobes, however, the grooves usually narrow considerably. Irregularities
in the width of the grooves are not uncommon, however. The ridges on
either side of the grooves and basal areas of the thallus without
grooves are flat to slightly convex. The
thallus and its lobes are usually grayish green overall and they have a
tendency to appear sparkly in bright sunlight. Older and decaying
sections of the thallus, however, usually become more white or light
purple, and finally orange red or brown.
The upper surface of the thallus has very fine
and shallow indentations from a fine network of single-pored cells.
These
angular-rounded cells are green toward their centers and whitish toward
their margins, providing the upper thallus surface with the appearance
of lizard skin. The bottom of the thallus is flat and largely light
green.
Sometimes there are short white hairs at the bottom of the notched tips
of the thallus lobes, but they are very few in number and quite
inconspicuous. This liverwort is monoecious, producing antheridia (male
sexual organs) and archegonia (female sexual organs) on the same plant.
These sexual organs are located near, or at, the upper surface of the
thallus and they are quite inconspicuous. After the sperm of the
antheridia fertilize the eggs of the archegonia of the same or
neighboring plants, the archegonia develop spore cases that become
mature
during late autumn or early winter. These spore cases are revealed as
inconspicuous bumps on the upper surface of the thallus, where they
remain embedded. The spores are not released to the outside world until
the surrounding thallus containing them deteriorates. The spores are
70-110 micrometers across, globoid in shape, and reticulated-warty.
These spores are small enough that they can be blown about by the wind
or transported by water.
Cultivation:
The preference is full
sun, moist to dry conditions, and a substrate containing clay, loam,
mud, sand, or gravelly material. While this liverwort can
adapt to surprisingly dry sites, it usually occupies microhabitats that
are more moist from depressions in the ground surface, or that are more
moist from the presence of nearby rocks or pavement. This non-vascular
plant is intolerant of competition from larger vascular plants. It has
been successfully cultivated in greenhouses.
Range
& Habitat: Lizard Crystalwort (Riccia
bifurca) is native to
Illinois, where it is apparently rare (see Distribution
Map).
This
liverwort was collected in Woodford County in 1937, and it was observed
in Vermilion County by the webmaster in 2016. Because this liverwort is
small and inconspicuous, and achieves its largest size only during the
autumn, it is probably more common within the state than these records
indicate. Lizard Crystalwort is widely distributed in North America,
Europe, Australia, and other parts of the world. In Illinois and
neighboring
areas, habitats for this plant include sandy banks along rivers,
exposed rocky outcrops, stubble fields, areas near
parking lots, exposed ground along roadside ditches, and barren waste
areas. This plant is a pioneer ephemeral
species that usually colonizes open disturbed areas, although it also
occurs in barren natural areas.
Faunal
Associations:
Little is known about
floral-faunal relationships for this little plant. It is possible that
vertebrate animals and some invertebrate animals (e.g., earthworms) may
play an important role in spreading the spores to new locations. For
example, the tiny spores can probably cling to the muddy feet of
vertebrate animals and the shoes of humans. They may also cling to the
sticky bodies of earthworms or pass through their gullets while
remaining viable.
Photographic
Location: Near a parking lot and picnic area at
Kickapoo State Park in Vermilion County, Illinois.
Comments:
The non-vascular plants, liverworts, are usually found in either
wetlands or damp shaded woodlands. Lizard Crystalwort (Riccia
bifurca)
and several other Crystalwort species (Riccia spp.)
are unusual in
their ability to colonize surprisingly dry and sunny sites.
Distinguishing among Crystalwort
species is rather difficult as they superficially appear rather similar
to each other. All of these species are small in size (usually less
than 1" across) and relatively flat, consisting of dichotomously
branched thalli. Lizard Crystalwort can be distinguished from several
similar
species using the following set of criteria: 1) the upper surface of
its thallus lacks conspicuous cavities, unlike Riccia
cavernosa and Riccia sullivantii, 2) the
lower margins of its
thallus lobes lack
significant hairs, unlike Riccia beyrichiana and Riccia
hirta, 3) the
grooves along the upper surface of its thallus lobes are usually quite
wide, except at the tips of its lobes, while Riccia sorocarpa
and Riccia hirta have narrow grooves throughout,
and 5)
its thallus lobes are tongue-shaped, rather spoon-shaped like Riccia
frostii.
Other characteristics to be considered are the shape of thallus margin
(flattened, swollen, or wall-like), size and appearance of the spores,
and overall size of the thallus lobes. These are fascinating little
plants that are worthy
of further study. Unfortunately very few people pay any attention to
them. An obsolete scientific name of Lizard Crystalwort is Riccia
arvensis.