Write an account of classification of Algae given by F. E. Fritsch.

Ans. A contribution which stands out is the most comprehensive and authoritative account of the classification of algae given by the greatest phycologist of our times, F.E. Fritsch (1935) in his voluminous work which was published in the form of a book “Structure and Reproduction of the Algae” volume one. The second volume of this book came out after ten years and both these volumes contain by far the most detailed account of algae. The monumental work by the great phycologist brought about a sense of relief to many workers in this field and at the same time, it paved way for further work and research. He classified algae into eleven classes as follows:

Class I. Chlorophyceae: It corresponds to Isokentae of the older classification. The members of this class are green or grass-green in colour. The chief pigments are chlorophyll a and b accompanied by small amount of yellow pigments.

The class is characterised by the presence of pyrenoids (except Siphonales) and thus starch as chief food material.

Reproduction takes place by vegetative, asexual and sexual means. Sexual reproduction is accomplished with the help of motile gametes having equally oriented cilia. It ranges from isogamy to oogamy.

The members occur mostly in fresh water though terrestrial and marine forms are also not uncommon.

Class II. Xanthophyceae: It corresponds to Heterokontae. The members of this class are yellow-green with xanthophyll as chief pigment. They lack pyrenoids and, therefore, food material is not starch but oil.

In sexual reproduction, the motile gametes possesses two unequal cilia. Most of the members inhabit fresh water and few are marine.

Class III. Chrysophyceae: The orange colour algae have phycocyanin as the main pigment and are uninucleate.

True starch is always lacking. The food consists of oil and leucosin. The members of this class are fresh water and marine but prefer cold waters.

Class IV. Bacillariophyceae: The forms included in this class are yellow or golden brown or even olive green in colour. They are beautiful to look at. They are also known as Diatoms and the chief pigment is Diatomin,

but Molish regards phaeophyll as the main pigment which he considers as brown modification of chlorophyll.

Pyrenoids are present. Members are unicellular or may form colonies but they are always diploid. The presence of motile phase is a matter of doubt.

A special type of sexual fusion takes place. The forms are fresh water and marine.

Class V. Cryptophyceae: The colour of the members of this class is very much variable. They may be brown, red, olive green or even blue green. The true nature of pigments is not known though, according to Pascher, they may be similar to those of Dinophyceae.

There are two large parietal chloroplasts having pyrenoids. Forms are fresh water and marine.

Cysts are known in many species and their development is endogenous.

Class VI. Dinophyceae : The members are dark yellow or brown. The chief pigments, according to Schutt, are red phycoerythrin, dark red peridinin and yellowish green chlorophyllin. The three pigments are collectively called pyrophyll. The food is in the form of starch and fat.

There are many discoid chloroplasts and the nucleus is large and prominent.

Class VII. Chloromonadineae :The members of this class are bright green with excess of xanthophyll. Food is in the form of fat. There are numerous discoid chloroplasts.

Reproduction takes place by longitudinal division of the individuals. However, very little is known about this class.

Class VIII. Euglenineae: Most of the members of this class lack chromatophores but Holophytic Euglenineae possess many chloroplasts of green colour.

According to Fritsch, they are the naked flagellates and their origin is supposed to be obscure. According to him, they ‘show a more definite trend in the direction of animal organization”.

Class IX. Phaeophyceae : Commonly known as a brown algae, their chief pigment is fucoxanthin. Plant structure is complicated.

Reproduction is vegetative and sexual. The male reproductive organs have two unequal lateral cilia, one pointing forwards and the other backwards. They are produced on special structures. The female is liberated sometime before fertilization. The forms are mostly marine.

Class X. Rhodophyceae: The members of this class are beautiful red or dark red in colour. The chief pigment is phycoerythrin along with some phycocyanin. The food material is floridean starch.

There are no motile phases in the life history of an individual. Sexual reproduction is highly oogamous. The members are mostly marine.

Class XI. Myxophyceae : Also known as Cyanophyceae, the members of this group are blue green in colour. Phycocyanin is the chief pigment in addition to chlorophyll and carotenoid.

The cell structure is very simple. So much so, that even a well defined nucleus is lacking. A cell has nucleoplasm or centroplasm in centre and chromoplasm at periphery.

There are no motile phases at any time in the life-history of its members. The reproduction takes place only by vegetative means. Sexual reproduction is unknown.

The members of this class occur almost everywhere.

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