The zygote is the first cell that develop into sporophyte. The zygote inside the venter increases in size and divides repetitively by mitotic division to form a small embryo. Now the embryo continue its division and finally form an elongated sporophyte.
The sporophyte consists of a bulbous foot and a cylindrical, erect capsule (seta absent). In between foot and seta an intermediate meristematic tissue zone is present.
Foot: The foot is deeply inserted within the gametophytic tissue. this foot is made up of thin walled parenchyma cells. The main function of foot is to absorb water and nutrients from the gametophyte to supply to the capsule.
Meristematic tissue: The meristematic tissue is an unique feature of Anthoceros sporophyte, due to continue division of this tissue the capsule get elongated.
Capsule: The erect capsule is an elongated, slender, cylindrical in structure. It may be of 2-3 cm, (in some species it may be up to more than 10 cm.) It looks like a horn or bristle, thats why the genus is known as hornwort.
The capsule has 3 distinct zones, ie. a) The central columella
b) The middle archesporium or sporogenous tissue zone
c) The covering wall layers
a) Columella: At the central portion of the capsule a cylindrical, supportive, pillar like tissue appearance is found, known as columella. It consists of 16 vertical rows of sterile cells. The main function of it is to provide mechanical support to the capsule.
b) Archesporium or sporogenous tissue: The surrounding of the columella the next tissue zone is known as archesporium, it mainly consists of sporogenous tissue. From the base to apex of the cpsule different stages of development of spores from archesporium tissue are found.
At the very bottom of the capsule only single layer of archesporim cells are found, next upwards the other successive stages like spore mother cells, spore tetrad, free spores and pseudoelaters are found. Pseudo-elaters are the multicellular elongated structures, help in spore dispersal. Here spore mother cells divide meiotically and form haploid spores.
c) Wall layers: Surrounding the sporogenous tissue zone the next outer covering layer is known as wall layers or jacket layers. This zone is multi layered (4-6), the most outer cell layer is epidermis, this epidermis layer is cutinised and carries stomata in place to place. The next inner layer to the epidermis is chloroplast bearing photosynthetic green tissue.
Capsule dehiscence:
The dehiscence in capsule is apex to base orientation (basipetally). The dehiscence is usually performed by two longitudinal dehiscence line. At maturity due to dehydration of the jacket layer, it starts to dehisce through the lines and form two valves of the capsule wall. Now the expossed inner mass of spores are being loosen by the hygroscopic movement of pseudo-elaters and air current helps indispersal of the spores.
Germination of the spore:
Under favourable condition the liberated spore germinates by formation of a germ-tube. The germ tube finally grows and form the young thalloid gametiphytic thallus of Anthoceros.
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