COMMENTS ON PELLIA
Habit
Pellia is a terrestrial genus found in moist shady wood, soil rocks, by the side of streams, springs and ditches.
Vegetative structure
i) Gametophytic plant:
The gametophytic plant body is small breast green prostrate, this dorsiventral, thallus. It is dichotomously branched with wavy lobed margins. Each branch terminals into a median apical notch where the growing point is located.
ii) Dorsiventral thallus:
The dorsal surface is smooth and marked by thickered mid ribs in the middle. The ventral surface beams numerous unicellular smooth walled rhizoids.
The thallus is thick at the middle but gradually reduces in thickness towards the periphery.
Sexual reproductive structures.
i) Oogamous:
The sexual reproduction is oogamous conducted by the male and female sex organs, called antheridium and archegonium respectively. The thallus is either homothallic or heterothallic.
ii) Antheridia
In a homothallic plant, the numerous water-like projection on the dorsal surface towards midrib represents the antheridial chambers. They open outside by a small opening called ostioles. It is spherically shaped standing on a multicellular short stalk. It consists of a single layered jacket enclosing numerous androcytes cells or antherozoids.
iii) Archegonia:
The archegonia are found in duster on a slightly raised side of the receptacle Just behind the apical notch and lie horizontally. The archegonia remains covered by a delicate Membrane called in voliere originated from neighbouring cells.
The archegonium is a multicellular short stacked flask-shaped body with dilated venter and long neck. The wall of the neck is layered and consists of five rows of vertical neck cell’s surrounding 6-9 neck canal cells. The top of the archegonium is covered by four large cover cells.
Sporangium or sporophyte
The sporangium is an elongated structure consisting of foot, seta and capsule. The foot is a basal conical mass of parenchymatous cells firmly embedded in the thallus. Its projecting upper edge surrounds the base of the seta-like collar.
The seta is a cylindrical elongated structure resting on foot and is composed of longitudinal rows of cells.
i) Capsule:
The terminal end of the seta bean globose capsule is surrounded by two layered jackets. It consists of a number of large spores arranged in tetrahedral tetrads, elaters and elaterophores.
ii) Elaterophore
It is elongated erect, stout, spirally thickened sterile cells formed in a bunch.
iii) Elater:
It is slender spindle-shaped sterile cells possessing spirally thickened bonds on the walls. The Spore remains intermixed with free elaters.
