Introduction

The group of non-mobile polyphyletic living organisms falls under the category of thallophytes. Thallophytes are also referred to as thallophyta or thallobionta. Thallophytes are identified and classified based on the presence of identical or similar characteristics. Although they do not have a common ancestral origin, they are grouped under one class based on other similar features. The body of thallophytes does not contain a vascular system and hence conducting tissues are absent. The types of living organisms falling under thallophytes include algae, slime molds, fungus, and lichens. 

Thallophyta is a division of the plant kingdom including primitive forms of plant life showing a simple plant body. Including unicellular to large algae, fungi, lichens. Thallophytes (Thallophyta, Thallophyto, or Thallobionta) are a polyphyletic group of non-motile organisms traditionally described as “thalloid plants”, “relatively simple plants” or “lower plants”.  

Characteristics of Thallophyte

Some of the important characteristics of thallophyta are given below:

• Thallophyta sex organs are single-celled
• Once the fertilization is done or over, there is the provision of forming an embryo
• It is unlike other plants, meaning there is no presence of phloem or xylem found
• Vascular tissue is absent in this plant
• These plant cells don’t have a cellulose cell wall
• One of the main characteristics of the thallophyta is that there is the release of glucose after photosynthesis and this part is consumed immediately. The rest part of glucose is changed into starch, a kind of complex compound
• The plant stores food in the form of starch
• Many members of the groups manufacture their food. Also, a few of them, for instance: fungi are dependent for their food on other sources. They are autotrophic
• This group member is mostly found in wet or moist areas
• It doesn’t have vascular tissue and “true roots” which are needed to make connections for minerals and water. Hence, they are found in wet and moist places
• The plant members of this group are one of the most primitive forms of plants. Their body is not differentiated into leaves, stems, and roots. They appear to have undistinguished thallus. The group is commonly called algae
• Their sexual reproduction took place by the fusion of two gametes
• There may or may not be any changes of generation present or available. The life cycle may be classified into diplohaplontic, diplontic, or diploid
• The body of the plants is divided into different parts like leaves, stems, or roots

Division of Thallophyta

The plant class Thallophyta is sub-divided into two subdivisions: Algae and Fungi.

Algae

These are thalloid-bearing chlorophyll. They are autotrophic plants and rare aquatic plants. In this plant, it has been seen that green algae do a symbiotic relationship with fungi that are prominent in the lush tropical rainforests of South America and Central America. Sloth fur is very fine and easily absorbs water. Hence, sloth fur builds a moist and damp environment for the algae to grow. The algae in return provide the sloth with more nutrition and camouflage from predators. Example: Spirogyra.

The basic characteristics of algae are provided here:

• Algae do not have any leaves, stems, or roots
• To do photosynthesis, they have chlorophyll as well as other forms of pigments
• Algae can be both unicellular and multicellular
• Many of the time in the water, the unicellular algae are found, specifically in plankton

Classification of Algae

1. Chlorophyceae: They are commonly called green algae. Mostly they are found in freshwater. They contain pigments chlorophyll a and b, hence they are grass green in color.

The shape of chlorophyll may be discoid, plate-like, reticulate, cup-shaped, spiral, or ribbon-shaped in different species.

Examples: Chlamydomonas, Volvox, Spirogyra.

1. Phaeophyceae: They are commonly called brown algae. Primarily they are marine algae. They possess chlorophyll a,c, carotenoids, and xanthophylls.

Examples: Ectocarpus, Dictyota, Laminaria.

1. Rhodophyceae: They are commonly called Red algae because of the predominance of the red pigment, r- phycoerythrin in their body.

Examples: polyphonic, Porphyra, Gelidium.

Fungi

Fungi are achlorophyllous and non-mobile thallophytes. The cell wall of fungi is made up of chitin.

Fungi are incapable of synthesizing their food due to the absence of chlorophyll. Thus, fungi depend on other living entities to derive their food.

One such combination is with the algae. Fungi live in symbiosis with algae since they are chlorophyllous. Algae offer food to fungi while fungi protect algae from harmful UV rays. This type of existence where two organisms support each other’s survival is called symbiosis. An example of a fungus living in symbiosis with algae is the lichen. Algae and fungi both act as a single unit.

Some of the characteristics of fungi are:

• They are non – motile they cannot move
• They are known as the best recycler in the plant kingdom
• Unlike a plant, instead of cellulose, chitin is used to make up the cell walls

Conclusion

Thallophytes are plants that include the category of lichens, fungus, algae, and slime moulds. These are found in moist and wet places. These plants lack true roots and vascular tissues which are needed to transport water and minerals to all the parts of the plants. Hence, these are found in moist and wet places. These plants are autotrophic.