Tag: botany

A unique feature of hornwort is that the sporophytes, unlike that of mosses and liverworts, continue to grow from their bases for the remainder of the gametophyte's life, a characterstic known as indeterminate growth. Hornwort sporophytes are characterised by a basal (or intercalary) meristem that continuously develops new sporangial tissue (indeterminate growth). However, the sporangium does not grow indefinitely.

Pyrenoid is an aggregate of protein, almost exclusively Ribulose 1,5-bisphosphate carboxylase/oxygenase and some minor proteins.These are defined as bodies in chloroplasts that reacted strongly with protein stains. They are generally absent in Bryophytes but present in Anthoceros.

Liverworts are distributed worldwide, though most commonly in the tropics. Thallose liverworts grow commonly on moist soil or damp rocks, while leafy liverworts are found in similar habitats as well as on tree trunks in damp woods. Western Himalayas are having abundance growth of liverworts which are also mentioned by Prof S.R.Kashyap in his  two famous books ' Liverworts of Western Himalayas and Punjab Plains' Part I (1929) and Part II (1932).

In Riccia, the sporogonium which is the sporophyte individual differs from the thallus (gametophytic plant) in structure, function and genetic constitution as well. The thallus is green in colour and autotrophic. The sporogonium has no colour and is heterotrophic in its nutrition. The thallus represents the haplophase where as the sporogonium represents the diplophase. Unlike other liverworts, the embryo, sporogonium and spore mother cells in Riccia do not develop chloroplasts. The sporophyte remains totally dependent on the thallus for food materials, water and minerals in solution.

The sporogonium of Riccia never dehisces. The spores are liberated by the decay or shrivelling of the surrounding outer layer of the calyptra and thallus tissue. The thallus perishes in the dry season. The spores remain behind on the soil. In this condition, they may be dispersed by the wind.

The sporophyte of Riccia is the simplest because as it contains only capsule, both the foot and seta are absent. It consists a peripheral layer of cells constituting the capsule wall and a central mass of spore mother cell which produces spores.

A leptoid is a type of elongated food conducting cell analogous to phloem in vascular plants. It is found in the stem-like structure of certain mosses, like those belonging to family Polytrichaceae. They surround strands of water and mineral conducting elements the hydroids, analogous to trachieds in vascular plants.

Sphagnum is the scientific name of peat moss. It is also called as bog moss. It has high pH. Hence, it is used for plants growing in acidic condition, such as blueberries. It helps in moisture absorption from soil.