1. The document provides information on the study of algae being conducted by Apeksha Shrikant Kurane for her Cryptogamic Botany course. 2. It discusses the general characteristics of algae including being chlorophyll-bearing, aquatic or forming symbiotic relationships, and reproducing both asexually through spores and sexually. 3. The document covers various topics related to algae including their thallus organization from unicellular to multicellular forms, different habitats from aquatic to terrestrial, and various modes of reproduction including vegetative, asexual through spores or akinetes, and sexual reproduction.

1. 🤗Welcome🤗

2. Name – Apeksha Shrikant Kurane
Subject – Cryptogamic Botany
Course – TY Bsc.Bed (Sem 5th)
Title – Study Of Algae
Teacher – Dr. Sarika Torawane
Savitribai Phule Pune
University
•Department of Education & Extension •

3. • Title :-
Study of Algae

4. Introduction -
 Algae are group of lower Cryptogamic Plants
 The term Algae were first introduced by Linnaeus in 1753
 Single cell as small as 1 micrometer to large seaweeds which can
grow up to more than 60 m. It is an important group of Thallophyta (
Thallos – a sprout, Phyton – a plant)
 The orderly systematic study of Algae is called Phycology ( Phycos –
Seaweeds, Logos – Study )

5. General characteristics :-
1. Algae are chlorophyll – bearing Autotropic thalloid plant body.
2. Almost all the algae are aquatic & free living, although some can form a symbiotic relationship
with other organism.
3. The plant body may be unicellular to large robust multicellular structure.
4. Algae lack a well – defined body, so, structure like; roots, stem or leave are absent. Algae are
found where there is adequate moisture
5. The sex organs are generally unicellular but, when multicellular, all cells are Fertile &, in most
cases, the entire structure does not have any protection jacket.
6. Plant having distinct alternation of generation. Both gametophyte & sporophyte generation when
present in the life cycle are independent.
7. Reproduction in algae occur in both asexual & sexual forms. Asexual reproduction occur by spore
formation.

6. Distribution of Algae :-

7. Thallus organizations :-
 Range of algal thallus varies from unicellular to multicellular
forms or microscopic to macroscopic structure, with their size
ranging from a few microns to some meters.
 Micromona spusilla is known to be smallest algae which is
unicellular & is 1 micrometer on the Other hand giant kelps has
longest thalli that reaches up to 60m (200ft.) In length.
 The other intermediate stages considered in thallus
organizations of algae are palmella, dendroid, palmelloid,
coccoid, filamentous, siphonaceous, heterotrichus, unaxial,
multiracial, etc

8. 1) Unicellular forms :-
 Unicellular or cellular forms can be motile or non – motile & are further grouped
into three categories based on presence or absence of flagella.
 The motile forms are either rhizopodial or flagellates & non – motile forms are
concord.

9. A) Rhizopodial :-
 The rhizopodial forms lack rigid cell wall and have a naked
protoplast, cell envelope is periplasmic, soft & permits extensive
changes in shape & size of thallus, lack flagella & instead possess
cytoplasmic projection called Pseudopodia & Rhizopodia. These
forms move in amoeboid manner.
 Examples – Chrysamoeba (Chrysophyseae), Rhizochloris
(Xanthophyceae), Dinophyceae.

10. B) Flagellates :-
 The vegetative phase of many algae is a motile, flagellate unicell. Flagella may be
1 or 2 or many, equal or unequal, tinsel or whiplash type. Motile unicells are
commonly Spherical, elongate, ovoid or round in cross section.
 Examples – Flagellated forms are present in almost all groups of algae except
Myxophyceae, Phaeophyceae, Rhodophyceae.

11. C) Coccoid :-
 Non – Motility predominates & Motility is entirely absent or Restricted only to
reproductive stages. Occur in majority of algal classes & predominates in
Xanthophyceae (70%). Coccoid forms are provided with a rigid cell wall & are
non – flagellates.
 Examples – Prochloron, Aphanocapsa & Synechococcus.

12. 2) Multicellular forms :-
(A) Colonial Aggregation -
 A colony is a group of separate cells generally similar in structure &
function & aggregated by a mucilaginous envelope number of cells
arranged in a particular manner
 It comprises aggregation of flagellate (Volvox) or non – motile
(Hydrodictyon)

13. (B) Palmelloid :-
 Colonial members in which ‘Non – motile’ cells remain embedded
in anamorphous gelatinous or mucilaginous matrix. In this type
neither the number, nor the shape & size of cells is constant. The
cells are aggregate in a common mucilaginous envelope.
 Example – Palmella, Microcystis.

14. (C) Tetrasporal :-
 The motile stages are restricted to the reproductive cells. The regular colonies of
the Cyanophyceae ( e.g. – Merismopedia, Halopedia as flat plates of cell & Eucapis,
with colonies in cubical masses) are included in the Tetrasporal types. A feature of
tetrasporial form is the is presence of mucilaginous psedocilia.

15. (D) Dendroid :-
 The cells are united in a branching manner by localized production of
mucilage at the base of each cell. The whole colony looks like a tree in
habit.
 Example – Chrysodendron

16. (D) Filamentous forms :-
 Filamentous are formed when vegetative division occur in a
transverse plane. In a filament the uniseriate row of cells are joined
end to end in a transverse plane through middle lamella. In
Cyanophyta, a filaments include both the trichomes (i.e., the
uniseriate row of cell) & its sheath. The filaments may be Branched or
unbranched.

17. Unbranched filaments
Examples – Spirogyra, zygonema, Oedogonium,
Ulothrix

18. Branched filaments
Examples – Cladophora, Pithopora
the branching of the filaments is either true pr false.

19. (G) False Branching :-
 It occur in Scytonemataceae (Cyanophyta), the trichomes generally
fragments due to the degeneration of an intercalary cell after which
one or both of its ends adjacent to the dead cell grows out of the
parent sheath, giving there resemblance of branching.

20. (H) True Branching :-
 It result repeated transverse division of the lateral outgrowths produced by a few
or many scattered cell of the main filament. The truly branched thalli are of four
types :
1) Heterotrichous
2) Parenchymatous forms
3) Pseudoparenchymatous forms
4) Siphonocladous organization

21. Heterotrichous :-
 The thallus consists of two parts, a prostrate creeping base & an erect branched
upright system.
 Ex – stigeoclonium (Chlorophyta) & Ectocarpus (Phaeophyta)

22. Parenchymatous forms :-
 This occur when cell of the primary filament divide in all direction any essentially
filamentous structure is thus lost early.
 Ex – Porphyra, Ulva.

23. Pseudoparenchymatous forms :-
 This habit result from a close juxtaposition of branched filaments of a single or
many axial filaments.

24. Siphonocladous organisation :-
 It is restricted to members of Chlorophyceae in which the unbranched (Urospora,
Chaetomorpha) or branched (Cladophora) filaments are composed of
multinucleate cells.

25.  Habit and Habitat
ALGAE ARE GROUP OF UBIQUITOUS ORGANISMS HAVING
DIVERSE HABITATS SUCH AS; WATER (AQUATIC ALGAE), LAND
(TERRESTRIAL ALGAE), THEY ALSO GROW AS AN EPIPHYTE,
ENDOPHYTE, & AS WELL AS IN EXTREME CONDITION & HAS
UNIVERSAL OCCURRENCE.

26. (1) Aquatic Algae :-
 Mostly algae are aquatic & are found in fresh water growing in ponds, pools,
lakes, rivers, tanks, etc., in blackish water as well as marine water.
 Ex – Nostac Oedogonium Cladophora

27. (2) Planktonic Algae :-
 They float freely on the surface of water & can be further differentiated
into
 (A) EUPLANKTONIC – True planktons which are free floating from the
beginning & never get attached to the substratum. E.g. – Volvox,
Cosmarium, Chlamydomonas, etc.
 (B) TYCHOPLANKTONS – Initially these algae attached to the
substratum but later they detach & become free floating, E.g. –
Cladophora, Zygnema, etc.

28. (3) Benthic Algae :-
 These algae are bottom dwellers i.e. attached to the bottom of shallow pool.
 Ex – Ulothrix, Tribonema minus.
(4) Neutronic Algae :-
 These algae grow at air water interface. The algae growing in sea water are
commonly known as marine algae (Seaweeds)
 Ex – Botrydiopsis, Chromatophyton

29. (5) Supralittoral :-
 These algae grow above the water level & are found growing on the rocky shore
where they are just dampened only by the splashes of high spring tide waves such
as; Prasiola stipitate, Ulothrix flacca, etc.
(6) Sublittoral or Infra Littoral : -
 These algae below the water level. Some common examples of algae growing in
brackish water are : Oscillatoria, Anabaena, etc.

30. (7) Littoral :-
 These algae grow in the areas where there is periodic exposure of
tides & is a junction between land & sea
 Some of the examples of algae growing in this sub-tide zone are
Dictyota sp., Rhodymenia sp., Gracilaria sp., Laminaria sp., etc.
 Algae growing in intertidal zones are Porphyra sp., Euglena sp., Fucus,
etc.

31. (8) Aerophytes :-
 Algae growing on the surface of leaves, bark, flower pots, rocks, fencing,
wires are grouped as aerophytes.
 Bark of trees (Epiphloeophytes) Trentepholia, Scytonema, Chroococus,
Pleurococcus
 Surface of leaves (Epiphyllophytes) Phycopeltis epiphyton, Somatochroon,
Somatochroon, Cephaleuros.
 Rocks & stones Cyanoderma, Trichophilus,
Trentopholia,

32. (9) Cryophytic Algae :-
 These algae grow in permanent or semi – permanent mountain & Polar region of
the world. These algae when grow impacts colour to the snow
 Examples –
 Red colour Chlamydomonas nivalis, Scotiella,
Gloeocapsa
 Brown / purple colour Acyclonema
 Green colour Chlamydomonas stonensis, Euglena
Enkistrodesmus
 Yellow / yellowish green colour Scitiella, Protoderma, Pleurococcus,
Nostac.
 Black colour of snow Raphidonema

33. (10) Endozoic Algae :-
 Algae growing inside the body of vertebrates or aquatic animals are called
endozoic algae.
 Examples –
 ALGAE  HOST
Zoochlorella Hydra viridis
Zooxanthella Fresh water sponges
Oscillatoria, Simonsiella,
Anabaemiolum
Several vertebrates

34. (11) Epizoic algae :-
 Many algal forms are know to grow on the surface of other
aquatic animal.
 Examples –
 Oscillatoria, Protoderma, Bascicladia &
Dermatophyte
On the surface body of Turtles
 Cladophora crispata Shells of snails & Molluscs
 Stigeoclonium Gill & nose of fish

35. (12) Epiphytic Algae :-
 These grow on other aquatic plants & are not host specific
 Examples –
 ALGAE  HOST
Coleochaete nitellarum Chara & Nitella
Chaetonema Tetraspora & Batrachospermum
Rivularia Scirpus; an angiosperm
Chaetophora Leaves of Nelumbo & Vallosnaria
Cocconis, Achanthus Lemna

36. (13) Halophytic Algae :-
 These algae grow in water with very high salinity may be up to 70 – 80 ppt
 Ex – Dunaliella, Stephanoptera, Oscillatoria, Ulothrix.
(14) Symbiotic Algae :-
 Members of cyanophycean algae grow in association with several plants such as;
Nostoc grows in association with Blasia, Notothylas and Anabaena azollae grows
in Azolla.

37. (15) Parasitic Algae :-
 Members of algae are known to live ass parasite & semi – parasite on other algae
as well as higher plants, e.g. Cephaleuros Virescence (Chlorophyceae) grown on
tea plants (causes Red rust of Tea) Cephaleuros virescence (Chlorophyceae) grow
on Coffea arabica, semi parasite Ceratocolax (Rhodophyceae) grown in
Phyllophora thallus

38. (16) Terrestrial Algae :-
 Algae growing on soil, logs, rocks, etc. are grouped under terrestrial
algae.
 Ex – Vaucheria, Oedocladium
(17) Thermophytic Algae :-
 These algae grow in hot spring, where the temperature may go
beyond 85c
 Ex – Synechococcus, Phormidium, etc.

39. REPRODUCTION
ALGAE REPRODUCE BOTH ASEXUALLY AS WELL AS SEXUALLY.
THE ASEXUAL METHOD OF REPRODUCTION INCLUDES
REPRODUCTION BY VEGETATIVE METHODS &
REPRODUCTION BY SPORES. THE DIFFERENT METHODS OF
REPRODUCTION BY SPORE.

40. 1. Vegetative Reproduction
 The vegetative reproduction is a type of reproduction
where a part of thallus becomes specialized & gets
detached from the parent to form a new individual thus
formed in this way is genetically identical to parent & no
variation is observed. The different ways by which algae
reproduces vegetatively are ; Budding, cell division,
fragmentation, etc.

41. Budding :-
 Some vesicles which get detached from the parent plant by the
formation of septum, & are cable of giving rise to a new thallus is
called Buds
 Ex – Protosiphon

42. Cell Division :-
 Simplest method of reproduction, where, the unicellular
algae divide into two by fission.
 Ex – Chlamydomonas, Diatoms.

43. Fragmentation :
 During this process the filamentous thalli breaks into two or many fragment. Each
fragment is capable of giving rise to a new filaments. The fragmentation may
result due to accidental breakage or formation of separation of disc.
 Ex – Spirogyra, Nostoc, Oscillatoria

44. Bulbils– these are tuber like outgrowth developed mostly at the Rhizoidal tips.
Ex – Chara
Hormogones– these are short segments within the sheath of parents
filaments. Commonly found in members of Cyanophyceae.
Amylum– present on lower nodes of Chara. These are star shaped
aggregation of starch.

45. 2. Asexual Reproduction / Reproduction by spores
AKINETES : These are thick
walled spores with abundance of
food reserve. They withstand the
unfavourable conditions &
germinate on the onset of
favourable conditions.
 Ex – Nostoc, Gloeotrichia, Ulothrix,
Cladophora, Pithophora

46.  AUTOSPORES – During unfavourable conditions protoplast inside
the sporangium divides & forms spores which are identical to parents
plant. They are non – motile, thick walled & abundant in food reserve.
EX – Chlorella, Scenedesmus.
 APLANOSPORES – They may be formed singly / by the repeated
division of the sporangium of parent plant during unfavourable
condition. EX – Ulothrix
 BISPORES – When 2 spores are formed in a sporangium, they are
called bispores & the sporangium is termed as bisporangium as
reported in Grateloupia fillicina.

47. CARPOSPORES -
 These are formed in carposporangium during triphasic life cycle of
Rhodophyceae members. They are formed from zygote & are diploid in nature.
 Ex – Polysiphonia, Gracilaria.

48. ENDOSPORES -
 These are formed in the sporangium by successive repeated division of cell
contents. All spores are formed first, then the sporangium opens to liberate
the motile spores.
 Ex – Dermocarpa clavata.

49. EXOSPORES -
 During exospore formation in Cyanophycean members, the sporangium gets burst
at the apex & is exposed to the external environment & further by successive
repeated divisions of cell content the spherical spores are formed which are
termed exospores
 Ex – Chamaesiphon, Stichosiphon

50. ZOOSPORES -
 The motile & naked spores are known as zoospores. They may be haploid /
diploid & formed in zoosporangium. Zoospores may have 2, 4 or more flagella.
 Ex – Chlamydomonas, Ulothrix

51. 3. Sexual Reproduction
Sexual reproduction has been reported from all members of algae except
cyanophycean. In sexual reproduction, 2 opposite gametes fuse to form a zygote.
Depending on the structure & behaviour of fusing gametes, it can be classified as :
 ISOGAMY – In it fusion gametes are similar i.e. they are morphologically &
physiologically similar.
 Ex – Chlamydomonas, Ulothrix

52.  ANISOGAMY – In it the fusion gametes are an Dissimilar gametes i.e. they
are morphologically & physiologically not similar & are different. EX –
Chlamydomonas, Braunii
 OOGAMY – It is an advanced type of sexual reproduction & has been
observed in higher plants & animals too. In algae, usually male partner is motile &
female partner is non – motile with exception in Rhodophyceae. In algae the male
antherozoids are formed in Antheridium & female gametes are formed in
Oogonium. EX – Oedogonium, Chara.

53. Classification of Algae (G.M. Smith)
DIVISION CLASSES EXAMPLES
 Chlorophyta Chlorophyceae Volvox
Charophyceae Chara
 Euglenophyta Euglenophyceae Euglena
 Pyrrophyta Cryptophyceae Cryptomonas
Desmokontae Desmarestia
Dinophyceae Dinophysis
 Chrysophyta Xanthophyseae Botrydium
Chrysophyceae Chromolina
Bacillariophyceae Pinnularia
 Phaeophyta Isogenerateae Ectocarous
Heterogenerateae Mynomena
Cyclosporeae sargassum
 Cyanophyta Myxophyceae Nostoc, Anabaena
 Rhodophyta Rhodophyceae Polysiphonia, Gracilaria