This lecture is about classification of algae. In this presentation outline of Fritsch's and Smith's classifications are given. Helpful for B. Sc. students.
2. The primary classification of algae is based on the following
five criteria:
❑ Photosynthetic apparatus and pigments
❑ Nature of reserve food
❑ Nature of cell wall components
❑ Type, number and attachment of flagella
❑ Cell structure
3. ➢F.E. Fritsch (1935, 1948) published his classification in his book
entitled “The Structure and Reproduction of the Algae”.
➢He divided algae into following 11 classes on following basis:
❑ Number and mode of attachment of flagella in the motile cells
❑ Thallus structure
❑ Chemical nature of pigments
❑ Reserve food materials
❑ Method of reproduction
❑ Variation in the life cycles
4.
5. ❑ Main pigments are Chlorophyll a, Chlorophyll b, Carotenoids and Xanthophylls
❑ Reserve food material is starch
❑ Chloroplasts have pyrenoids
❑ Starch grains are usually aggregated around the pyrenoids
❑ Flagella, if present, are of equal length, whiplash type and inserted at the anterior end
Class Chlorophyceae has been divided into following nine orders:
1) Volvocales (e.g. Volvox)
2) Chlorococcales (e.g. Chlorella)
3) Ulotrichales (e.g. Ulothrix)
4) Cladophorales (e.g. Cladophora)
5) Chaetophorales (e.g. Fritschiella)
6) Oedogoniales (e.g. Oedogonium)
7) Conjugales (e.g. Zygnema)
8) Siphonales (e.g. Vaucheria)
9) Charales (e.g. Chara)
6. ❑ Main pigments are Chlorophyll a, Chlorophyll e, β-carotene and xanthophylls
❑ Reserve food material is oil
❑ Pyrenoids are absent
❑ Flagella, if present, are two, unequal and inserted anteriorly. The short
flagellum is of whiplash type and the longer one is tinsel shaped
Class Xanthophyceae has been divided into following four orders:
1) Heterochloridales (e.g. Heterochloris)
2) Heterococcales (e.g. Myxochloris)
3) Heterotrichales (e.g. Tribonema)
4) Heterosiphonales (e.g. Botrydium)
7. ❑ The main pigment is phycochrysin which gives brown or orange colour
to these algae
❑ The reserve food material is chrysolaminarin and leucosin
❑ Pyrenoids are naked
❑ Flagella, if present, are two equal or unequal in length, inserted at the
anterior end
Class Chrysophyceae has been divided into following
three orders:
1) Chrysomonadales (e.g. Chrysodendron)
2) Chrysoaphaerales (e.g. Chrysosphaera)
3) Chrysotrichales (e.g. Chrysoclonium)
8. ❑ The main pigments are fucoxanthin, diatoxanthin and diadinoxanthin
❑ The reserve food materials are fat and volutin
❑ Pyrenoids are present
❑ Motile cells have single flagellum
❑ Cells are unicellular, diploid and divided into two halves
Class Bacillariophyceae has been divided into following
two orders:
1) Centrales (e.g. Cyclotella)
2) Pennales (e.g. Navicula, Pinnularia)
9. ❑ The main pigment is xanthophyll
❑ The reserve food material is starch and/or oil
❑ Pyrenoids are present but often independent of chromatophores
❑ Mainly plants are motile cells and most advanced forms are coccoid;
flagella are slightly unequal and anteriorly inserted
Class Cryptophyceae has been divided into following two
orders:
1) Cryptomonadales (e.g. Cryptomonas)
2) Cryptococcales (e.g. Tetragonidium)
10. ❑ Main pigment is xanhophyll which imparts brown or red colour.
❑ Chromatophores are numerous, discoid, dark yellow, brown etc.
❑ Reserve food materials are starch and oil
❑ Plants are unicellular motile to branched filamentous. The body of motile
cells has two furrows, one is transverse having transverse flagellum which
encircles the body and the other is longitudinal with backwardly directed
longitudinal flagellum
Class Dinophyceae has been divided into following six orders:
1) Desmomonadales (e.g. Desmocapsa)
2) Thecatales (e.g. Exuviaella)
3) Dinophysales (e.g. Dinophysis)
4) Dinoflagellata (e.g. Ceratium)
5) Dinococcales (e.g. Dinastridium)
6) Dinotrichales (e.g. Dinothrix)
11. ❑ The main pigment is xanthophylls which is present in excess;
Chromatophores are numerous, discoid and bright-green in colour
❑ The reserve food material is fat and oil.
❑ Pyrenoids are absent
❑ The plants are motile flagellates with two almost equal flagella
❑ Sexual reproduction is absent, multiplication is takes place by
longitudinal division of cells.
Class Chloromonadineae has only one order:
1) Chloromonadales (e.g. Trentonia)
12. ❑ The main pigment is chlorophyll; each cell has many chromatophores
which are pure green
❑ The reserve food material is polysaccharide paramylon
❑ Pyrenoid like bodies are found in some forms
❑ The plants are motile flagellates; flagella may be one or two arising
from the base of canal-like invagination at the front end.
❑ Multiplication by cell division
Class Euglenineae includes following three families:
1) Euglenaceae (e.g. Euglena)
2) Astasiaceae (e.g. Astasia)
3) Peranemaceae (e.g. Anisonema)
13. ❑ The main pigment is fucoxanthin besides chlorophylls a and c
❑ The reserve food material is alcohol (mannitol), polysaccharide (laminarin)
and fats
❑ Some lower forms have naked pyrenoid like bodies
❑ The motile reproductive cells have two lateral or sub-apical flagella; one
directed forward and the other backward
❑ Fucosan vesicles are found in cells
Class Phaeophyceae includes following nine orders:
1) Ectocarpales (e.g. Ectocarpus)
2) Tilopteridales (e.g. Tilopteris)
3) Cutleriales (e.g. Cutleria)
4) Sporochnales (e.g. Sporochnus)
5) Desmarestiales (e.g. Desmarestia)
6) Laminariales (e.g. Laminaria)
7) Sphacelariales (e.g. Sphacelaria)
8) Dictyotales (e.g. Dictyota)
9) Fucales (e.g. Fucus)
14. ❑ The main pigments are two types of phycobilins: r-Phycoerythrin and r-
phycocyanin besides chlorophylls a and d
❑ The reserve food material is solid polysaccharide: the floridean starch
❑ Some lower forms have pyrenoid like bodies
❑ Motile stages are totally absent.
❑ Pit connections are present
Class Rhodophyceae includes following seven orders:
1) Bangiales (e.g. Bangia)
2) Nemalionales (e.g. Batrachospermum)
3) Gelidiales (e.g. Gelidium)
4) Cryptonemiales (e.g. Corallina)
5) Gigartinales (e.g. Gigartina)
6) Rhodymeniales (e.g. Champia)
7) Ceramiales (e.g. Polysiphonia)
15. ❑ The main pigments are chlorophyll a, β-carotene, c-phycocyanin and c-
phycoerythrin;
❑ Well developed chromatophores are absent due to prokaryotic type of cell
organization
❑ The reserve food materials are sugars, glycogen and cyanophycean starch
❑ No motile stages are known
❑ Sexual reproduction is absent
Class Myxophyceae includes following five orders:
1) Chroococcales (e.g. Chroococcus)
2) Chamaesiphonales (e.g. Chamaesiphon)
3) Pleurocapsales (e.g. Pleurocapsa)
4) Nostocales (e.g. Nostoc)
5) Stigonematales (e.g. Stigonema)
16. ➢Smith (1933, 1951, 1955) gave classification of algae on the
following basis:
❑ Characters of vegetative cells
❑ Morphology of motile reproductive cell
➢He divided algae into seven divisions, then classes were
included in each division.
17.
18. ❑ Mostly fresh water, a few marine
❑ Chlorophyll a and b are dominant pigments
❑ Reserve food is starch
❑ Motile reproductive cells have two to four flagella which are anteriorly
inserted, equal and of whiplash type
Chlorophyta includes two classes:
1) Chlorophyceae
2) Charophyceae
19. ❑ Plants are fresh water and terrestrial
❑ Chlorophyll a, b and β carotene are dominant pigments
❑ Reserve food is paramylum and fats
❑ Motile cells have one, two or three flagella, anteriorly inserted into a
narrow gullet
❑ Multiplication takes place usually by cell division
Euglenophyta includes only one class:
1) Euglenophyceae
20. ❑ Organisms are mainly unicellular and rarely colonial
❑ Chlorophyll a, c, β carotene and xanthophylls are main pigments
❑ Reserve food is starch and/or oil
❑ Motile cells have two anteriorly inserted unequal flagella
❑ Cell wall is made up of cellulose
❑ Sexual reproduction is rare
Pyrrophyta includes two classes:
1) Desmophyceae
2) Dinophyceae
21. ❑ Most of the plants are fresh water (about 75 %) and rest are marine
❑ Main pigments are carotene and xanthophylls
❑ Reserve foods are leucosin and oil
❑ Cell wall is composed of two over-lapping silicified halves
❑ Sexual reproduction varies from isogamous to oogamous type
Chrysophyta includes three classes:
1) Chrysophyceae
2) Xanthophyceae
3) Bacillariophyceae
22. ❑ Most plants are marine
❑ Main pigments are phycophein and fucoxanthin
❑ Reserve foods are polysaccharide (laminarin) and alcohol (mannitol)
❑ Cell wall is made up of cellulose, fucinic and alginic acids
❑ Sexual reproduction varies from isogamous to oogamous type
❑ Motile reproductive cells are pyriform in shape with two laterally
inserted flagella, one of which is whiplash type
Phaeophyta includes three classes:
1) Isogeneratae
2) Heterogeneratae
3) Cyclosporeae
23. ❑ Most fresh water plants, some species are free living, while others grow
on larger algae (epiphytic) or within the tissue of other plants
(endophytic)
❑ Cell is prokaryotic
❑ Main pigments are c-phycocyanin and c-phycoerythrin
❑ Reserve food is stored in the form of cyanophycean starch
❑ Cell wall is made up of cellulose, fucinic and alginic acids
❑ Sexual reproduction is absent; asexual reproduction takes place by
hormogonia, fragmentation and akinetes
❑ Motile cells are absent
Cyanophyta includes only one class:
1) Cyanophyceae or Myxophyceae
24. ❑ Mostly marine algaeMain pigments are r-phycoerythrin (due to which
this algae is red in colour) and r-phycocyanin
❑ Plant body is thalloid, non-motile and complex
❑ Reserve food is stored in the form of floridean starch
❑ Sexual reproduction is oogamous
❑ Motile reproductive cells are absent
Rhodophyta includes only one class:
1) Rhodophyceae
