BSc Botany Semester I

1. DIVERSITY OF PLANT KINGDOM
B.Sc. PART I SEMESTER I
BOTANY
Topic - RANGE OF THALLUS IN ALGAE
! ! J A I N A R S I N G H ! !
MEHTA P. G. COLLEGE
HARMARA, SIKAR ROAD, JAIPUR

2. AMIT KUMAR SHARMA
Dept. OF BOTANY
MCIT, HARMARA, JAIPUR
RANGE OF THALLUS
IN ALGAE

4. a) Freely moving in water by flagella.
b) They are of many shapes – spherical, oblong or pear
shaped and circular. Eg. Chlamydomonas
c) Some are dorsi-ventrally differentiated Eg. Phacus
d) The number of flagella may to one to more and it may
be equal or unequal.
1. Unicellular Algae:
It is of two types:
A. Motile forms or flagellated forms

5. Euglena – one flagellum at its anterior
Chlamydomonas – two flagella at its front end
Heterochlorsis – two flagella and unequal
Botrydiopsis – two flagella
Trichloris – three flagella
Carteria – four flagella
Chloraster – five flagella
Pocillomonas – six flagella
Carteria
Euglena
Chlamydomonas

6. B. Non-motileor Non-flagellated or Coccoid Forms
 The unicellular non – flagellated forms are called coccoid forms.
 The cells are more or less round and bounded by rigid cell wall
Eg. Chlorella and Chlorococcus
 The cell is elongated and spirally coiled structure
Eg. Spirulina
 The cell is spindle in shape Eg. Closterium
Closterium
Chlorococcus
CHLORELLA
Spirulina

7. 2. Multicellular Algae forms:
A group of individual cells of a species living in a habitat is called a
colony. It is of flowing types:-
A. Coenobium forms
B. Aggregation forms
C. Filamentous forms
D. Siphonous forms
E. Paranchymatous forms
F. Equisetoid form

8.  Coenobium is a colony of distinct shape, with a fixed number of cells
arranged in a specific or distinct manner.
 A further evolution of the unicellular with independent individual cells
types from occasional and indefinite type of colony.
It is of two types -
a. Motile colony forms
b. Non Motile colonial forms
A. Coenobium Forms

9. a. Motile colony forms:
Volvox colony has many cells interconnected by protoplasmic
connections. The surface of the colony is covered with mucilage.
Gonium colony consists of 4 – 32 closely arranged Chlamydomonas
type of cells surround by mucilaginous cells.
Pandorina colony has 16 – 32 cells covered with a common
mucilaginous sheath.
Volvox Gonium Pandorina

11. b. Non Motile colonial forms
The individual cells are non – flagellated as called non- motile
The group of non-motile colonial cells as called Coenobium.
Eg. Hydrodictyon, Pediastrum, Senedesmus etc.
 Hydrodictyon- Coenobium of Hydrodictyon consists of man
cylindrical cells which are joined end
to end like hexagons in shape. Hence
the colony appears to be a net-like.

12. Pediastrum colony is disc shaped and is
made of closely arranged cells.
 Scenedesmus colony consists of 4 – 8
variously shaped cells which are parellely
arranged.

13. B. AGGREGATION FORMS:
The aggregates are formed by the collection of single cells to
make thallus.
The aggregation of cells does not have a fixed number of cells and
irregular shape or size of the colony like mass.
They increase in the number of cells after division and the
daughter cells remain in same gelatinous mass.
The aggregates can be of three types:
(a) Palmelloid Forms
(b) Dendroid Forms
(c) Rhizopodial Form

14. Tetraspora
a. Palmelloid Forms
Numerous non motile cells are embedded in a
common mucilaginous matrix.
E.g.- Palmella, Tetraspora, Chlorosaccus etc.
Palmella

15. b. Dendroid forms:
The thallus appears as tree like under the microscope.
E.g.- Denobryon, Prasinocladus, Dendobryon etc.
Dendobryon Dinobryon

16. c. Rhizopodial form:
A colony in which the individual cells are linked
together by rhizopodia is called rhizopodial forms or
rhizopodial colony.
Eg. Chlorachnion.
Chlorachnion

17. C. FILAMENTOUS FORMS:
An algal thallus cells are arranged in linear row.
It formed through repeated cell divisions and all cells are
joined end to end forming a chain or a thread.
It is called a filament or filamentous form.
The filaments may be of two types:
a) Uniseriate filament or Unbranched filament
b) Multiseriate filament or Branched filament

18. a). Uniseriate filament –
The filament is made of single row of cells.
Eg. Ulothrix, Oedogonium.
b). Multiseriate filament –
The cells are arranged in more than one
linear row.
Eg. Ulva
Ulva
ULOTHRIX
Oedogonium

19. Branched filament or Multiseriate filament
Filamentous thalli with lateral branches is called branched
“filaments algae”.
Scytonema
Types of branched thalli
a. Pseudo branches
•In some algae, the filaments breaks at certain
points due to the disintegration of cells.
•The cells adjacent to the dead cells grow out of
the mucilaginous sheath called “Pseudo branches”.
Eg. Scytonema

20. True branches
The lateral branches arise due to the transverse
division of cells in lateral outgrowths.
Eg. Cladophora
 Parenchymatous cells
Eg. Ulva
 Pseudoparenchymatous cells
Eg. Cladophora, Polysiphonia, Gracilaria

21. b. Heterotrichous forms
•The filaments which contains both prostrate system and erect system is
called “Heterotrichous form”.
• Hetero – different; trichous – filament
• The thallus was differentiated into creeping system and
projecting system.
• Creeping system – consists of branched filaments attached to the
substratum.
• Projecting system – arises from the creeping system and grows erect.

22. • Fritschiella – both creeping and erect equally
developed
• Coleochaete – creeping system – disc like and
well developed.
Projecting system – poorly developed
• Drapernoldiopsis– projecting system well
developed.
Creeping system – poorly developed.
Fritschiella
Coleochaete
Drapernoldiopsis

23. D. SIPHONOUS FORMS OR CEONOCYTIC ALGAE
 Elongated thallus without septation.
 The thallus cell is elongated which containsly nuclei, chromatophores,
cytoplasm and a central narrow mvacuole.
Eg. Vaucheria and Protosiphon

24. E. PARANCHYMATOUS FORMS
The plant body of algae made up of parenchyma cells. During the
cell =division septation leads to the formation of a parenchymatous
body. E.g.- Chara, Ulva, Sargassum
Chara Ulva Sargassum

25. THANK
YOU!!!