1. Riccia Ms. Inderveena Sharma H.O.D. Botany Department
P.G.G.C.G. 11, Chd.

2. CLASSIFICATION
Division: Bryophyta Class: Hepaticopsida Order: Marchiantiales Family: Ricciaceae Genus: Riccia

3. Gametophytic Plant Body
External Features
Gametophytic Plant Body
ventral surface of thallus
Plant body is a prostrate, flat, green, ribbon-shaped and dichotomously branched thallus.
The thallus is branched and has a dorsal median groove and ventral median ridge.
Rhizoids and scales are present on the ventral median ridge.
Rhizoids are numerous, unicellular, elongated, tubular and hair-like and are found as simple rhizoids or tuberculate rhizoids.
Scales are arranged in a transverse row and may be membranous, multicellular, single celled, and with colours ranging from pink, red, violet and black.
Scales contain anthocyanin pigment and when in water absorbs chlorophyll making it look green.

4. INTERNAL STRUCTURE OF THALLUS
Internal Features
INTERNAL STRUCTURE OF THALLUS
The upper assimilatory region is photosynthetic. It consists of numerous unbranched photosynthetic filaments arranged in vertical rows with a single row of cells, ending in the upper epidermis.
Upper epidermis is discontinuous and has non-green cells.
The lower storage region is a continuation of the upper assimilatory region and is parenchymatous.
They act as food storage cells.
Rhizoids and scales serve as anchors for the plant

5. Sexual Reproduction SEX ORGANS OF RICCIA
Sexual Reproduction is oogamous.
The male sex organ is the antheridium while the female sex organ is the archegonium
Sex organs develop in acropetal succession, ie. newer organs are formed at the apical lobe while older ones are pushed behind.
Sex organs lie embedded in the mid dorsal section of the thallus between air spaces and filaments.

6. T.S. of Mature Sporogonium
Structure Of Mature Sporogonium
T.S. of Mature Sporogonium
The sporogonium is embedded centrally in the tissue of gametophyte plant body
The mature sporogonium consist of mass of spores enclose within the outer layer of calyptra
The spores are generally attached in tetrads.
The calyptra layer is a part of gametophyte

7. Sexual Lifecycle of Riccia Showing Alternation of Generations
Lifecycle of Riccia has two distinct phases called haploid i.e. gametophytic and diploid i.e. saprophytic. These phases alternate with each other.
the gametophytic phase begins with the formation of haploid spores inside the sporogonium
gametophytic plant body is autotropic in its mode of nutrition
After reaching a certain stage of maturity, thallus starts producing sex organs
Male sex organs are antheridia and female sex organs are archegonia
Zygote formed after fertilization is diploid and it is the first cell of sporophytic generation
Sexual Lifecycle of Riccia Showing Alternation of Generations