Classification of Algae | Botany

In this article we will discuss about the Fritsch’s and Smith’s classification of algae.

1. Fritsch’s Classification:

The algae have broadly been divided by F. F. Fritsch in 1935 into eleven classes according to their colour:

i. Chlorophyceae or green algae, e.g. Chlamydomonas, Volvox, Oedogonium, Spirogyra, Vaucheria, Chara, etc.

ii. Xanthophyceae or yellow—green algae e.g. Botrydium.          

iii. Chrysophyceae.

iv. Bacillariophyceae or golden-brown algae e.g. Diatom.

v. Cryptophyceae.

vi. Dinophyceae.

vii. Chloromonadineae.

viii. Eugleninae.

ix. Phaeophyceae or brown algae, e.g. Fctocarpus, Laminaria, Dictyota, Fucus, etc.

x. Rhodophyceae or red algae e.g. Batrachospermun, Polysiphonia, etc.

xi. Myxophyceae or blue-green algae, e.g. Oscillatonia, Nostoc, etc.

2. Smith’s Classification:

In 1955 C. M. Smith has classified algae into seven divisions, each of which contains one or more classes.

A brief account of this classification is given below:

i. Cyanophyta:

Cyanophyta or blue green algae-inhabitants of moist soil and rocks, fresh water or saline water; unicellular or colonial; plastids not well-defined; presence of nucleoplasm in the centre of the cell and chromoplasm in the periphery; nucleus is primitive; phycocyanin is the chief pigment but sometimes phycoerythrin may be present; sexual reproduction and flagellated cells are always ab­sent; reproduction is vegetative or asexual by resting spores; gly­cogen is the reserve food.

Examples:

Oscillatoria, Nostoc, Gleocapsa, etc.

ii. Chlorophyta or Green Algae:

They are found in fresh water or saline water; unicellular, multicellular or colonial; cells flagellated or non-flagellated; reproduction is asexual or sexual; presence of chlorophyll, carotin and xanthophyll like higher plants; reserve food is starch.

Examples:

Spirogyra, Oedogonium, Ulothrix, Vaucheria, Chara, etc.

iii. Euglenophyta:

Found in fresh water or stagnant water or on moist soil; cells flagellated or naked; coloured plastids promi­nent; cell divisions longitudinal; reserve food is paramyleum (a kind of carbohydrate).

Example:

Euglena

iv. Pyrophyta:

Chiefly marine; unicellular; presence of two unequal flagella; yellowish green or yellowish brown pigments present; sexual reproduction is rare; reserve food is starch or oil.

v. Chrysophyta:

Chiefly consists of Diatoms; terrestrial, fresh water or saline water; flagellated or non-flagellated; unicellular or multicellular, colonial or filamentous; cell wall made of pectin with deposition of silica particles on the surface; of the pigments carotin and Xanthophyll are present in abundance; special method of sexual reproduction; oil and leucosin (a complex carbohydrate) are reserve food.

The division consists of three classes, of which Bacillariophyceae is the main plants consisting of this class are known as Dia­toms or golden brown algae; the yellow pigment diatomin is always present with chlorophyll.

vi. Phaeophyta or Brown Algae:

Chiefly marine; plant body large and complicated by the presence of pigment like fucoxanthin and phycophene; both sexual and asexual reproduction take place; sexual reproduction is isogamous and oogamous carbohydrate and oil are reserve food.

Examples:

Ectocarpus, Fucus, etc.

vii. Rhodophyta or Red Algae:

Chiefly marine; plant body is very complex; main pigment is phycoerythrin; sexual reproduction is oogamous; male gametes known as spermatia, are non-flagel­lated; reserve food is Florideam starch. 

Examples:

Batrachospermum, Polysiphonia, etc.