Riccia
Encyclopedia
Riccia is a genus of liverwort
s in the order Marchantiales
. One of the more than 100 species in this genus is the "slender riccia" (Riccia fluitans
), which can be found floating in ponds, and is sometimes used in aquariums.
The plant body is a thallus that is not differentiated into root, stem and leaf. The thallus is dorsiventrally differentiated, and is dichotomously branched to form a rosette. The upper (dorsal) surface of the thallus is green with a mid-dorsal sulcus (furrow or groove) and tiny air pores.
The lower (ventral) surface has a mid-ventral ridge bearing a single row of multicellular scales on either side of the ridge. The scales are multicellular and violet due to a pigment anthocyanin
. There are numerous unicellular rhizoid
s of two types on the ventral surface. One type is called smooth and the other type is the pegged or tuberculated rhizoids; these help in anchorage and absorption. The inner surface of the smooth rhizoids is smooth while that of the tuberculate rhizoid will have internal cell wall
projections.
Marchantiophyta
The Marchantiophyta are a division of bryophyte plants commonly referred to as hepatics or liverworts. Like other bryophytes, they have a gametophyte-dominant life cycle, in which cells of the plant carry only a single set of genetic information....
s in the order Marchantiales
Marchantiales
Marchantiales is an order of thallose liverworts that includes species like Lunularia cruciata, a common and often troublesome weed in moist, temperate gardens and greenhouses....
. One of the more than 100 species in this genus is the "slender riccia" (Riccia fluitans
Riccia fluitans
Riccia fluitans, whose common name is crystalwort, is an aquatic floating plant of the liverwort genus Riccia which is popular among aquarists as a retreat for young fry and is used in live-bearing tanks. It can be found floating in ponds, and often forms thick mats on and under the water...
), which can be found floating in ponds, and is sometimes used in aquariums.
The plant body is a thallus that is not differentiated into root, stem and leaf. The thallus is dorsiventrally differentiated, and is dichotomously branched to form a rosette. The upper (dorsal) surface of the thallus is green with a mid-dorsal sulcus (furrow or groove) and tiny air pores.
The lower (ventral) surface has a mid-ventral ridge bearing a single row of multicellular scales on either side of the ridge. The scales are multicellular and violet due to a pigment anthocyanin
Anthocyanin
Anthocyanins are water-soluble vacuolar pigments that may appear red, purple, or blue according to pH...
. There are numerous unicellular rhizoid
Rhizoid
Rhizoids are thread-like growths from the base or bottom of a plant, found mainly in lower groups such as algae, fungi, bryophytes and pteridophytes, that function like roots of higher plants ....
s of two types on the ventral surface. One type is called smooth and the other type is the pegged or tuberculated rhizoids; these help in anchorage and absorption. The inner surface of the smooth rhizoids is smooth while that of the tuberculate rhizoid will have internal cell wall
Cell wall
The cell wall is the tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to...
projections.