chara

1. Course Code: Bot-301
Course Title: Diversity of
Plants
Credit Hours: 3(2-1)
Dr. Riffat Nasim Fatima and
Dr. Sana Tehseen
Assistant professor
Department of Botany
GCWUF

2. Content
Taxonomic Position of Chara
Occurrence
Structure
Cell Structure
Thallus Growth

3. • So far seven living genera with about
294 species have been recoded
• These are;
• Chara (27 species)
• Tolypella ( 3 species)
• Nitella (37 species)

4. • Nitellopsis (single species)
• Lychnothamnus (single
species)
• Lamprothamnium
• Protochara

5. Taxonomic Position
Division Charophyta
Class Charophyceae
Order Charales
Family Characeae
Genus Chara

6. Occurrence
• Chara is a fresh water, green
alga
• Found submerged in shallow
water ponds, tanks, lakes and
slow running water
• C. baltica is found growing is
brackish water and C. fragilis
is found in hot springs.

7. • Chara is found mostly in hard fresh water, rich in organic matter,
calcium and deficient in oxygen
• Chara plants are often encrusted with calcium carbonate and hence
are commonly called stone wort
• Chara often emits disagreeable onion like odour due to presence of
sulphur compounds

8. • C. hatei grows trailing on the soil
• C. nuda and C. grovesii are found
on mountains
• C. wallichii and C. liydropitys are
found in plains

9. Thallus Structure
• The thallus of Chara is branched,
multicellular and macroscopic
• The thallus is normally 20-30 cm. in
height but often may be up to 90 cm to l
m

10. • Some species like C. hatei are small and may be 2-3 cm. long
• The plants in appearance resemble Equisetum hence Chara is
commonly called as aquatic horsetail
• The thallus is mainly differentiated into rhizoids and main axis

11. Rhizoids
• The rhizoids are white, thread like,
multicellular, uniseriate and branched
structures
• The rhizoids arise from rhizoidal plates
which are formed at the base of main axis
or from peripheral cells of lower nodes

12. • The rhizoids are characterized by presence of oblique septa
• The tips of rhizoids possess minute solid particles which function
as statoliths
• Rhizoids help in attachment of plant to substratum, in absorption
of minerals and in vegetative multiplication

13. Continue..
Main Axis
• The main axis is erect, long,
branched and differentiated
into nodes and internodes
• The internode consists of
single, much elongated or
oblong cell

14. The inter-nodal cells in some species may be
surrounded by one celled thick layer called
cortex and such species are called as corticate
species
• The species in which cortical layer is absent
are called ecorticate species
• The node consists of a pair of central small
cells surrounded by 6-20 peripheral cells
• The central cells and peripheral cells arise
from a single nodal initial cell

15. • On nodes develop these following four types of appendages:
• i- Branches of limited growth
• ii- Branches of unlimited growth
• iii- Stipulodes
• iv-Cortex

16. Branches of limited growth
• The branches of limited growth
arise in whorls of 6-20 from
peripheral cells of the nodes of
main axis or on branches of
unlimited growth

17. • These are also called branchlets, branches of first order, primary
laterals or leaves
• These branches stop to grow after forming 5-15 nodes and hence
are called branches of limited growth
• The stipuloides and reproductive structures are formed on the
node of these branches

18.  Branches of unlimited growth
• The branches of unlimited
growth arise from the axils of the
branches of limited growth
• Also called auxiliary branches or
long laterals

19. • Branches of unlimited growth are differentiated into nodes and
internodes
• At nodes they bear primary laterals and these branches look like
the main axis
• Their growth is also unlimited like main axis

20. Stipulodes • The basal node of the
branches of limited growth
develops short, oval,
pointed single cell
outgrowths called
stipulodes
• In most of the species of
Chara e.g., C. burmanica,
the number of stipulodes at
each node is twice the
number of primary laterals,
known as bistipulate
species

21. • In some species of Chara e.g., C. nuda and C. braunii, the number of
stipulides at each node, is equal to number of primary laterals at that
node such species are called unitipulate
• When stipulodes are present in one whorl at each node the species
are called as haplostephanous
• When two whorls on each node are present then it is known as
diplostephanous

22. iv-Cortex
• Many species of Chara e.g., C. aspera, C. inferma have inter-nodal
cells of main axis en-sheathed by cortex cells
• Such species are called corticated species
• The cortex consists of vertically elongated narrow cells

23. • The internode up to half of its length by corticating filaments
developed from upper node called descending the lower half of
internode is covered by filaments developed from lower node called
filaments
• The ascending and descending filaments meet at the middle of
internode
• The species without cortex e.g., C. corallina are called ecorticated
species

24. Ascending and
Descending growth
in Chara

25. Cell Structure
• Young cells are uninucleate
• They do not have vacuoles
• The mature cells develop a large
central vacuole

26. • Its nuclei divide b. amitosis and it becomes multinucleate
• Cells have many chloroplasts
• These chloroplasts are spirally arranged in the peripheral portion
of cytoplasm

27. • Chloroplast contains pigments chlorophyll a, chlorophyll b and
Xanthophyll
• The reserve food material is starch
• The cytoplasm shows cyclic moments

28. References
• R.E. Lee. Phycology. 2008. Cambridge University Press
• https://www.biologydiscussion.com/algae/life-cycle-
algae/chara-occurrence-structure-and-reproduction-
algae/21135