FRULLANIA

CLASSIFICATION OF FRULLANIA

Kingdom :-  Plantae

Division :- Bryophyta

Class :- Hepaticopsida

Order :- Jungermanniales

Family :- Frullaniaceae

Genus :- Frullania

EXTERNAL MORPHOLOGY OF FRULLANIA​

• The plants are large or medium sized but rarely small. These are reddish-brown or nearly black in colour.
• The plant body is a gametophyte. It is differentiated into a branched, prostrate, central, stem-like axis and the leaves.
• The thallus is attached to the substratum by unicellular, smooth walled rhizoids which arise in tufts from the bases or middle of the amphigastria.
• The prostrate stem is pinnately or bipinnately branched.
• The leaves on the stem are arranged in three rows-two rows of lateral leaves and a row of underleaves or amphigastria. Each lateral leaf is bipartite forming a large expanded antical lobe and a small postical lobe.
• The antical lobe is obliquely ovate or suborbicular and almost always entire.
• The postical lobe, also called lobule is cucullate, galeate or saccate. It may either form a water sac or may remain open. 8. The postical lobe usually bears a short subulate process, the stylus near its attachment between the postical lobe and the stem.
• Unde rleaves or amphigastria are usually smaller. These are rounded, notched or deeply lobed.

ANATOMY OF THE STEM OF FRULLANIA​

• s. of the stem is almost circular in outline.
• Well defined epidermis is absent.
• The section shows cortical and medullary regions.
• The cortex is 2 to 3 cells deep. It consists of small cells with distinct thickened pigmented walls.
• The central part is called medullary region. It is made of large and elongated cells with thin colour less walls.

ANTHERIDIAL BRANCH AND ANTHERIDA OF FRULLANIA

• The species of this genus are dioecious as well as monoecious.
• Monoecious species are autoicous i.e. antheridia and archegonia are borne by different branches.
• The antheridia occur in the axils of bracts (perigonial bracts) borne on short laterals.
• The perigonial bracts are densely imbricate and are divided into two almost equal lobes, large in size.
• There are usually two antheridia in the axil of each bract.
• A mature antheridium consists of a stalk and a body.
• The stalk is slender and multicellular being composed of two rows of cells.
• The body of the antheridium is globose. It consists of a central mass of androcyte mother cells and one-celled wall or jacket.
• Androcyte mother cell divides, each forming two biflagellate antherozoids.

ARCHEGONIAL BRANCH AND THE ARCHEGONIUM​ OF FRULLANIA

• The archegonia occur in groups at the apices of short lateral branches. Each group has two to four archegonia.
• A group of archegonia is surrounded by 2 to 5 pairs of perichaetial bracts which are dentate or lobed and larger than foliage leaves.
• The inner pairs of bracts are connate with each other.
• The uppermost bracts are laterally fused to form perianth.
• The perianth is inversely heart shaped and much contracted to form a small, tubular mouth.
• A mature archegonium is a flask shaped structure consisting of a basal ventre and the upper neck.
• The venter has two layered wall that surrounds a small egg cell and a venter canal cell situated just above it.
• The neck consists of five vertical rows of neck cells which surround an axial row of eight neck canal cells.

SPOROPHYTE OF FRULLANIA

• A mature sporophyte consists of foot, seta and capsule.
• The foot remains embedded in the tissue of the female branch.
• The seta is very short and only 8-9 cells thick. It is not very distinct from the capsule because of the mass of thin walled tissue at the base of the capsule (resembling apophysis of moss sporogonium).
• The capsule wall is made of two layers of cells.
• The cells of the outer layer have thick rod-like fibres on their lateral walls especially at the comers.
• The cells of the inner layers have walls with irregular network of thickening fibres.
• Inside the wall there are about 80 elaters and large number of spores.
• The elaters run from the roof to the floor of the capsule. These alternate with vertical rows of spores. Each elater is flattened. It has a single broad spiral band of thickening. The lower end of the elater is trumpet shaped.
• The spores are large, oblong to roundish. The wall is two layered, the exospore and the endospore. The exospore is rough, tuberculate and verrucose. The cytoplasm has a nucleus and a chloroplast.

IDENTIFICATION

• DIVISION – Bryophyta
  1. True roots absent and instead are present the rhizoids.
  2. No true vascular strands.
• Class:- Hepaticopsida
  1. Rhizoids without septa
  2. Chloroplasts without pyrenoids
  3. Columella absent from capsule and there are stomata on capsule wall.
• Order– Jungermanniales
  1. Scales absent.
  2. Rhizoids smooth walled.
  3. Antheridia and archegonia are borne at the apices
  4. Archegonial neck consists of 5 vertical rows of cells.
  5. Gametophyte with stem and two rows of dorsal, and a third ventral row of leaves.
  6. Archegonia in a terminal cluster and the last archegonium is formed by the apical cell.
• Family – Frullaniaceae
  1. Stems usually pinnately branched.
  2. Rhizoids form a tuft at the base or middle of the under leaf.
  3. Lateral leaves complicate-bilobed.
  4. Perianth compressed and obtrusely triangular in cross section
• Genus – Frullania
  1. Branch develops from the ventral half of a lateral segment replacing lobule of the leaf.
  2. Presence of stylus.