Classification of Algae

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.

1. by
Dr.RakeshKumar
V. S. P.Govt.(P. G.)College,Kairana, Shamli (U. P.)

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
❑Thallusstructure
❑Chemical nature of pigments
❑Reserve food materials
❑Method of reproduction
❑Variation in the life cycles

5. ❑Main pigments are Chlorophyll a, Chlorophyll b, Carotenoidsand 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 Chlorophyceaehas 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
❑Pyrenoidsare 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 Xanthophyceaehas 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 phycochrysinwhich gives brown or orange colour
to these algae
❑The reserve food material is chrysolaminarinand leucosin
❑Pyrenoidsare naked
❑Flagella, if present, are two equal or unequal in length, inserted at the
anterior end
Class Chrysophyceaehas 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, diatoxanthinand diadinoxanthin
❑The reserve food materials are fat and volutin
❑Pyrenoidsare present
❑Motile cells have single flagellum
❑Cellsareunicellular,diploidanddividedintotwohalves
Class Bacillariophyceaehas 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
❑Pyrenoidsare present but often independent of chromatophores
❑Mainly plants are motile cells and most advanced forms are coccoid;
flagella are slightly unequal and anteriorlyinserted
Class Cryptophyceaehas been divided into following two
orders:
1)Cryptomonadales(e.g. Cryptomonas)
2)Cryptococcales(e.g. Tetragonidium)

10. ❑Main pigment is xanhophyllwhich imparts brown or red colour.
❑Chromatophores are numerous, discoid, dark yellow, brown etc.
❑Reserve food materials are starch and oil
❑Plantsareunicellularmotiletobranchedfilamentous.Thebodyofmotile
cellshastwofurrows,oneistransversehavingtransverseflagellumwhich
encirclesthebodyandtheotherislongitudinalwithbackwardlydirected
longitudinalflagellum
Class Dinophyceaehas 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. ❑Themainpigmentisxanthophyllswhichispresentinexcess;
Chromatophoresarenumerous,discoidandbright-greenincolour
❑Thereservefoodmaterialisfatandoil.
❑Pyrenoidsareabsent
❑Theplantsaremotileflagellateswithtwoalmostequalflagella
❑Sexualreproductionisabsent,multiplicationistakesplaceby
longitudinaldivisionofcells.
ClassChloromonadineaehasonlyoneorder:
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
❑Pyrenoidlike 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 Euglenineaeincludes following three families:
1)Euglenaceae(e.g. Euglena)
2)Astasiaceae(e.g. Astasia)
3)Peranemaceae(e.g. Anisonema)

13. ❑The main pigment is fucoxanthinbesides chlorophylls a and c
❑The reserve food material is alcohol (mannitol), polysaccharide (laminarin)
and fats
❑Some lower forms have naked pyrenoidlike bodies
❑The motile reproductive cells have two lateral or sub-apical flagella; one
directed forward and the other backward
❑Fucosanvesicles are found in cells
Class Phaeophyceaeincludes 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-Phycoerythrinand r-
phycocyaninbesides chlorophylls a and d
❑The reserve food material is solid polysaccharide: the florideanstarch
❑Some lower forms have pyrenoidlike bodies
❑Motile stages are totally absent.
❑Pit connections are present
Class Rhodophyceaeincludes 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 cyanophyceanstarch
❑No motile stages are known
❑Sexual reproduction is absent
Class Myxophyceaeincludes 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.

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
Chlorophytaincludes 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 paramylumand fats
❑Motile cells have one, two or three flagella, anteriorlyinserted into a
narrow gullet
❑Multiplication takes place usually by cell division
Euglenophytaincludes 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 anteriorlyinserted unequal flagella
❑Cell wall is made up of cellulose
❑Sexual reproduction is rare
Pyrrophytaincludes 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 leucosinand oil
❑Cell wall is composed of two over-lapping silicified halves
❑Sexual reproduction varies from isogamousto oogamoustype
Chrysophytaincludes three classes:
1)Chrysophyceae
2)Xanthophyceae
3)Bacillariophyceae

22. ❑Most plants are marine
❑Main pigments are phycopheinand fucoxanthin
❑Reserve foods are polysaccharide (laminarin) and alcohol (mannitol)
❑Cell wall is made up of cellulose, fucinicand alginicacids
❑Sexual reproduction varies from isogamousto oogamoustype
❑Motile reproductive cells are pyriformin shape with two laterally
inserted flagella, one of which is whiplash type
Phaeophytaincludes 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-phycocyaninand c-phycoerythrin
❑Reserve food is stored in the form of cyanophyceanstarch
❑Cell wall is made up of cellulose, fucinicand alginicacids
❑Sexual reproduction is absent; asexual reproduction takes place by
hormogonia, fragmentation and akinetes
❑Motile cells are absent
Cyanophytaincludes only one class:
1)Cyanophyceaeor Myxophyceae

24. ❑Mostly marine algaeMainpigments 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 florideanstarch
❑Sexual reproduction is oogamous
❑Motile reproductive cells are absent
Rhodophyta includes only one class:
1)Rhodophyceae