Classification of Bryophytes

The plant kingdom is so diverse and primitive. It ranges from ferns and mosses to huge trees. We can generally see them growing without any or minimal effort. The entire kingdom, scientifically known as Plantae, is divided into angiosperms (flowering plants), gymnosperms (non-flowering plants), thallophytes, Bryophytes, and pteridophytes. They have a pigment called chlorophyll that is responsible for the green colour in plants and they perform photosynthesis to make their food, so they are also called autotrophs.  Bryophytes are nothing but non-vascular, small plants, which include hornworts, liverworts, and mosses. They derive their name from the words Bryon, which means moss, and phyton, in turn referring to plants. Here, you will understand the classification of Bryophytes, along with their various characteristics.

Notably, this is an important topic in your NEET curriculum especially since it is one of the few classifications which happen to be high scoring. Apart from its classification, you will also develop an idea of bryophyte reproduction, which is also a crucial part of your curriculum.

Therefore, without further ado, let us get started!

Broadly speaking, Bryophytes can be divided into three categories. However, each category has further subdivisions under them as well. Consult the table below to further your understanding of Bryophytes classification.

Bryophyte Classification

Now that you know about the classification of Bryophytes, let us proceed to a detailed study of each.

Bryopsida: Characteristics

This class of Bryophytes contains nearly 1500 species, making it the largest class among the three. Also known as mosses, common examples of Bryopsida include polytrichum and funaria, among others.

The Characteristics of Bryopsida are Listed Below – 

• No elaters are present in the sporangium capsule.

• You can find their sex organs positioned apically along the stem.

• Foliose includes a stem and lateral appendages (leaves). The former acts as an axis, while the midrib is absent on the leaves.

• Distinct presence of columella.

• Each sporophyte contains a capsule, foot, and seta.

• Oblique septa are present in multicellular rhizoids.

• Endothecium gives rise to sporogenous tissues.

Bryopsida: Reproduction

Bryopsida multiplies both sexually and asexually. Here is a brief look at both these processes. 

• Sexual Reproduction– The apical portion of shoots includes both archegonia and antheridia, which causes fertilization. The process produces a sporophyte, which, in turn, gives rise to the gametophyte.

• Asexual Reproduction– The secondary protonema grows and fragments, which leads to the formation of newer Bryopsida. Hence, asexual reproduction is complete.

Quick Question

1. What are three of the common bryophyte examples?

Ans: The most common examples are hornworts, mosses, and liverworts. 

Anthocerotopsida: Characteristics

Containing more than 300 species, Anthocerotopsida exhibit the following salient features – 

• Thallus shows no signs of scales.

• The gametophytic body comprises of a thalloid, without any internal tissue differentiation.

• Seta is meristematic.

• Sporophyte is cylindrically shaped. It only partially depends on the gametophyte to derive its nutrition.

Anthocerotopsida: Reproduction

As with the other two classes, reproduction in Anthocerotopsida occurs both sexually and asexually. 

• Sexual Reproduction– Water-borne sperm travels from the antheridium to the archegonium, fertilizing the egg. The developed sporophyte splits, releasing spores, which in turn, mature into gametophytes. 

• Asexual Reproduction– Thallus fragments and reproduces using tubers. Such a process occurs only in unfavorable conditions.

Hepaticopsida: Characteristics

The classification of Bryophytes is incomplete without Hepaticopsida. Here are some of this class’s salient features.

• Several chloroplasts are present in each thallus cell. However, chloroplasts are devoid of pyrenoids. 

• Columella is absent in the capsule.

• Reproductive organs are embedded within the dorsal surface.

• Septa absent in rhizoids.

• The plant body can be either foliose or thalloid. In the case of the former, lateral appendages or leaves do not contain a mid-rib.

Hepaticopsida: Reproduction

This type of Bryophyta can reproduce both sexually and asexually in the following ways – 

• Sexual Reproduction– Antheridium and archegonium lead to the formation of sperm and egg cells, respectively. After fertilization, a zygote is formed, which matures into a diploid sporophyte. After undergoing meiosis, this diploid sporophyte produces haploid spores, which transform into free-living gametophytes.

• Asexual Reproduction– Asexual reproduction depends on gemma cup fragmentation. These cups separate from the parent plant and become independent Hepaticopsida.

Economic Importance of Bryophytes

Bryophytes is crucial for the ecosystem, capable of performing a wide range of activities, which ensure survival for other beings.

• Prevention Against Soil Erosion

Certain bryophytes, such as mosses, form a cover over the topsoil. This matting prevents water erosion of this soil, preserving the natural soil structure.

• Medicinal Usage

Some classes of bryophytes are essential parts of the medical field. Medicines used in the treatment of gall bladder & kidney stones, liver afflictions, tuberculosis, eye infections, and much more. 

• Source of Food

Moss acts as one of the primary sources of food for certain mammals and birds. Without them, these creatures would likely perish or fail to derive the required nutrition.

• For Scientific, Research

Bryophytes are crucial in the field of genetic research. It can help in the determination of gender in plants.

• Water Retention

Sphagnum is one of the bryophytes that are essential for gardening and agriculture. It can retain around 25 times more water than its own weight, making it an ideal additive during seedling growth. 

Bryophytes Vs Pteridophytes:

Bryophytes and Pteridophytes belong to the same kingdom, the former ones do not have any vascular tissue like the xylem and phloem whereas the latter ones have vascular tissue and hence, they are called vascular plants. The body of the Bryophytes is similar to thallus and is leafy in nature. They have root-like parts to anchor the plant to the soil i.e, rhizoids. So they help in preventing soil erosion and consume less water compared to huge trees which also prevent soil erosion. The gametophyte is the sexual phase of a plant and it is dominant in the Bryophytes whereas the saprophytic phase is dominant in the Pteridophytes. In Bryophytes, antheridium i.e, the male sex organ is stalked but in Pteridophyte, it is attached to the base. Mosses, liverworts, hornworts are some of the examples of Bryophytes whereas spike mosses and ferns are examples of Pteridophytes. In Pteridophytes, vascular tissues like the xylem and phloem are present, the entire plant is clearly differentiated into stem, leaves, and roots. These types of plants have roots to anchor the plant to the soil, so they also help in preventing soil erosion. Bryophytes are also known as “amphibians of plant kingdom” as they need water for sexual reproduction. 

Make Your Lessons Count!

Now that you know about the classification of bryophytes, ensure you focus on other topics equally as well. Revise the entire biology curriculum thoroughly. Each topic may prove vital in your upcoming competitive examinations.

For instance, you must focus on pellia, riccia, Marchantia classification, etc. to score well in examinations. Also note, it is equally important to take care of your own self. Ensure that you provide sufficient rest to your body along with maintaining a healthy diet. Doing so will support your preparation, helping you achieve the desired results. Also, take some time to pursue recreational activities in between lessons, allowing your brain to recuperate.

All the best!