Notes

Types of Life Forms in Plant Community

The different types of life forms in plant community depend on their perennial organs. The term life form was coined by Raunkiaer, who divided life forms into five types based on the following characteristics.

The chosen character should be clear enough to see in nature.
The character should represent an important morphological adaptation and must be structural and essential.
The employed life forms must make a homologous system and must represent a particular aspect for comparison with other flora of different communities.

Types of Life Forms in Plant Community

Based on these, life forms are classified into

Phanaerophytes
Chamaeophytes
Hemicryptophytes
Cryptophytes
Therophytes

Phanaerophytes

Phanerophytes are plants that have perennating buds on the exposed branches or twigs during unfavourable conditions. Woody shrubs and trees, epiphytes, large perennial herbs, etc, are in this group. The plants can be divided into four classes according to their height.

Megaphanerophytes with buds at >30m
Mesophanaerophytes- 8 to 30m in height
Microphanaerophytes- 2 to 8 m high
Nanophanaerophytes- less than 2 m to >25cm.

These plants may further be classified into evergreen or deciduous, if the buds are protected by any scales or are naked, etc.

Chamaeophytes

These plants have shoot apices and buds on the shoots near the ground. They will have less than 25 cm in height. The buds that stay above the surface will be protected by fallen leaves or snow, as on their altitudes. They are classified into,

Subfructiose chamaeophytes, where the buds are protected by dead remains of the plant. Eg. Leguminosae, Caryophyllacea, Labiatae.
Passive chamaeophytes have their shoots lying on the ground. Polygonum, Saxifraga, Sedum, etc.
Active chamaeophytes have the buds lying on the ground but are protected by snow during unfavourable conditions. Eg. Vinca.
Cushion chamaeophytes form a transition stage between chamaeophytes and hemicryptophytes with closely packed shoots. Eg. Azolla.

Hemicryptophytes

Hemicryptophytes are seen on the soil surface with their shoots and buds safeguarded by dead leaves and soil. They are mainly herbaceous and can also be runners. They are further classified into rosette, partial rosette, and protochemicryptophytes.

Cryptophytes

Here, the shoots and buds are underground. These underground parts store their reserve food in subterranean perennating organs. They are,

Geophytes- land plants with subterranean buds which can be rhizomes, stem tubers, bulbs, root tubers, and roots.
Helophytes are plants living in water-saturated soil. Here, the flowers and leaves emerge above, and rhizomes are subterranean.
Hydrophytes are aquatic plants. Eg. Nelumbium

Therophytes

These are annual summer plants that will have all their parts die except the fruits and seeds.

References

Shukla, R.S. and Chandel, P.S. (2001) Plant Ecology. S. Chand and Company Ltd., New Delhi.
Verma, P.S., Agarwal, V.K. (1999). Cell Biology, Genetics, Molecular Biology, Evolution, and Ecology. New Delhi: S.Chand Co.(Pvt) Ltd.
https://landau.faculty.unlv.edu/lifeforms.htm