Funaria (Moss)

Systematic Position

• Kingdom: Plantae
• Sub Kingdom: Embryophyta
• Phylum: Bryophyta
• Class: Bryopsida
• Order: Funariales
• Family: Funariaceae
• Genus: Funaria

Funaria (Moss) Habitat

Funaria, commonly referred to as common moss, green moss, or cord moss, includes 117 species that are globally distributed. In India, 25 species have been documented, with Funaria hygrometrica, F. obtusa, F. attentua, and F. fasicularis being the most prevalent. Funaria thrives in recently burned grounds rich in plant ashes, favoring alkaline conditions. Typical habitats include moist rocks, walls, and grounds.

Also Check: Indirect Development in Biology

Funaria (Moss) Structure

External Structure (Gametophytic Phase)

The primary body of Funaria is the gametophyte, which exists in two forms:

1. Juvenile Form (Creeping Protonema)
2. Adult Form (Leafy Gametophore)

• Protonema: This branched, filamentous structure emerges from spore germination and is short-lived. The chlorophyll-containing portion near the substratum is known as chloronema, while the non-green, deeper, branched portion with oblique septa is the rhizoidal section.
• Leafy Gametophore: Buds formed on the protonema develop into this structure, consisting of an axis with spirally arranged leaves. It grows 1-3 cm in height, is green, and monopodially branched. The main branch bears male reproductive organs (antheridia), while the side branch is female. The phyllotaxy is 3/8 on the lower portion and 1/3 on the upper portion.
• Leaves: These are small, sessile, ovate with an acute apex and broad base, featuring a distinct midrib.
• Rhizoids: Located on the lower part of the leafy gametophore, these branched, multicellular rhizoids have oblique septa. Initially colorless, they darken at maturity due to the thickening of cell walls.

Also Check: Germination

Internal Structure

1. Stem: The axis is divided into the epidermis, cortex, and conducting strands (central cylinder). The epidermis is a single cell thick layer containing chlorophyll but lacking stomata and cuticle. The cortex comprises thin-walled cells with chloroplasts in younger parts, absent in older ones. The central cylinder consists of long, narrow, thin-walled, colorless cells devoid of protoplasm, facilitating conduction.
2. Leaf: Internally, a leaf consists of a several-cell thick midrib and a one-cell-thick lamina. The midrib contains a few conducting strands of narrow, thin-walled cells, while the lamina cells and some outer midrib cells house numerous chloroplasts.

Funaria (Moss) Reproduction

Funaria reproduces both vegetatively and sexually.

Vegetative Reproduction

This occurs through several methods:

1. Fragmentation of Primary Protonema: Primary protonema, formed from spore germination, may accidentally fragment, with each piece giving rise to leafy gametophores.
2. Secondary Protonema: Other plant parts like rhizoids and antheridia can develop protonema called secondary protonema, which in turn produces buds leading to leafy gametophores.
3. Bulbils: Resting buds formed on rhizoids and protonema detach and grow into new plants under favorable conditions.
4. Gemma: Multicellular structures called gemmae produced at leaf apices can separate and develop into new plants.
5. Apospory: Diploid cells from any sporophyte part separate and form protonema upon falling on the soil, leading to gametophyte-like plants with diploid cells without reduction division.

Also Check: Definition of Disease

Sexual Reproduction

Funaria plants are monoecious and autoecious, meaning male (antheridia) and female (archegonia) reproductive organs are found on the same plant but different branches. Male organs mature first, making Funaria protandrous.

1. Antheridium: The male branch, known as antheridiophore, bears antheridia at its tip. Surrounded by a rosette of leaves called perigonium, the antheridial cluster also contains green, multicellular sterile hairs known as paraphyses. The antheridium comprises a multicellular stalk and a club-shaped body with a one-cell-thick jacket, housing androgonial cells that eventually form biflagellate antherozoids.
2. Archegonium: Archegonia cluster at the tip of archegoniophore and are surrounded by ordinary foliage leaves and paraphyses. The archegonium is made of a stalk, venter, and neck. The venter contains an egg and a ventral canal cell, while the neck is composed of six vertical cell rows, holding neck canal cells. Cover cells cap the neck, and the sterile jacket is two-layered around the venter but single-layered around the neck.
3. Fertilization: Upon maturity, the antherozoids are released and swim towards the archegonium's neck, attracted by chemotactic substances, likely sugars. The antherozoid fuses with the egg to form a zygote, which immediately divides to form a sporophyte or sporogonium.

Sporophytic Phase

The fully developed sporophyte or sporogonium consists of three regions: basal foot, seta, and capsule.

• Basal Foot: Embedded in the female branch apex, it absorbs nutrients and supports the sporophyte.
• Seta: A long, slender, reddish-brown stalk bearing the capsule at the top. It is internally differentiated into a central cylinder for water conduction, surrounded by a thick-walled cortex and epidermis.
• Capsule: The terminal pear-shaped portion initially surrounded by calyptra, which later breaks up. The capsule has three parts: apophysis, theca, and operculum.
• Apophysis: The basal sterile part of the capsule continues with the seta. It has stomata for gaseous exchange, and chlorophyll-containing cells for assimilation, with a central zone acting as a conducting strand.
• Theca: The middle fertile zone of the capsule, between apophysis and operculum, houses the columella and spore sac. The columella supports the capsule, while the spore sac contains spores.
• Operculum: The upper cap-like part covering the peristome, separated from the theca by annulus and rim or diaphragm rings. The peristome has two whorls of 16 radially arranged teeth, with the outer exostome being hygroscopic and the inner endostome being non-hygroscopic.
• Dehiscence of Capsule: As the capsule matures, cells dry up, and the operculum separates, exposing the peristome. The peristome's hygroscopic action helps in spore dispersal, with spores having a long viability of 8-15 years.
• Germination of Spores: The spore, the first cell of the gametophytic generation, has an outer exosporium and inner endosporium. Upon favorable conditions, the spore germinates to form a branched, filamentous primary protonema, initiating a new gametophytic generation.

Also Check: Fragmentation in Biology

Funaria Structure Overview