Thallophytes are essentially ‘algae’ and Bryophytes are generally termed as ‘moss’ . Both have similarities like, the plant body being thalloid (branching, flat, ribbon-like) , they are auto-trophic, chloroplast pigments are similar, reserve their food material as starch, devoid of vascular tissues, are devoid of roots, gametophyte is the dormant phase and water is required for fertilization, to name a few.
However, despite their resemblances, there are some marked differences that set them apart, one from the other. A detailed list of differences is given below.
* Habitat:
Almost all Thallophytes are aquatic while Bryophytes are mainly terrestrial thriving in damp and shady areas.
* Habit:
Thallophytes consist of a single cell to filamentous structures with cells arranged end to end. Branching is irregular and tissue differentiation is not well defined. No division of labour for tissue. Chloroplast per cell is either one or two; not more. Pores / stomata are absent. Rhyzoids, if present, are simple. Growth and development is part of every cell.
In Bryophytes, plant body is parenchymatous with cells arranged in several layers. Branching of thalli is dichotomous. Tissue show no distinct differentiation; however they are modified for specialized functions. Division of labour of tissue is seen. There are may chloroplasts present. Stomata / pores are present. Rhizoids and scales are present. Rhizoids may be smooth walled or tuberculated. Growth and development is restricted to specialized cells.
* Reproduction:
In Thallophytes, reproduction is mainly asexual. When sexual, reproduction is isogamous, anisogamous or oogamous. Sex organs are single celled. Oogonium, the female sex organ is single celled which is typical of aquatic plants. Jacket and sterile vegetative cells are absent in the sex organs.
In Bryophytes, asexual reproduction is not seen. Vegetative reproduction may be observed. Reproduction is predominantly sexual in nature. Jacket cells are vegetative and sterile around the sex organs which are multi-celled. The female sex organ is the Archegonium which is characteristic of land plants. It consists of jacket cells, neck canal cells, and an egg cell.
* The Sporophyte:
In Thallophytes, the parent plant releases the zygospore. The zygospore goes through a resting phase before it germinates. It then goes through a phase of meiotic divisions to produce spores. The sporophyte constitute the independent stage in the life cycle. Plant exhibits ill-defined homogamous alternation of generation.
With regard to Bryophytes, soon after fertilization, the zygote germinates into the sporophyte while still in the parent plant. There is no resting phase. Plant exhibits heterogamous alternation of generation. Meiosis occurs later during the growth of the embryo. The sporophyte, once formed is still dependent on the mother plant and in most cases is released on the death of the parent plant.
Related articles and How-to Guides:
How to identify and classify Pelia
How to identify and classify Riccia
How to identify and classify Porella
How to identify Bryophytes
Bryophytes and Thallophytes: Similarities
