Siphonocladales is an order of multicellular, marine algae that have thalli attached to the substrate by rhizoids. They reproduce asexually through quadriflagellate zoospores and sexually through isogamous or oogamous reproduction. They are characterized by having multinucleate, coenocytic cells with reticulate chloroplasts and no pyrenoids. Siphonocladales uniquely divide their cells through a process called segregative cell division. They have been classified into 3 families: Siphonocladaceae, Valoniaceae, and Anadyomenaceae.

1. Manjunatha S
I M.Sc.(Botany)
University of Mysore
SIPHONOCLADALES

2. 1. Introduction
2. Characteristics of Siphonocladales
3. Segregative cell division
4. Classification
5. Conclusion
6. Reference
CONTENTS

3. 9. Cladophorales
10. Acrosiphoniales
11. Caulerpales
12. Siphonocladales
13. Dasycladales
14. Zygonematales
1. Volvocales
2. Tetrasporales
3. Chlorococcales
4. Chlorosarcinales
5. Chlorellales
6. Ulotrichales
7. Chaetophorales
8. Ulvales
CLASSIFICATION OF CHLOROPHYCEAE

4. Siphonocladales have multicellular thalli
attached to substratum by a system of Rhizoids and
divide in an unique manner called Segregative cell
division.
Introduction

5. Characteristics
Includes 18 genera and 150 species.
Exclusively Marine.
Cells are Multinucleate & Coenocytic.
Reticulate chloroplast.
Pyrenoids are Absent.
There are no Special Reproductive structures.
 Asexual reproduction by Quadriflagellate
Zoospores.
Sexual reproduction is usually Isogamous but it may
be Oogamous.

6. Segregative cell division
1.Cleavage of Protoplast
2.Secretion of Enveloping membrane
3.Increasing in size.
4.Expansion of segments
it may be a) Endogenous or
b) Exogenous

7. Exogenous type Eg: Siphonocladus tropicus

8. Endogenous type Eg: Dictyosphaeria cavernosa

10. CLASSIFICATION
Fritsch(1935), Printz(1927), Taylor(1942) Divided Order
Siphonocladales into 3 families namely
1. Valoniaceae
2. Dasycladaceae
3. Cladophoraceae
Borgensen(1925), Egerod(1952) Feldmann(1938) placed Dasycladaceae
and Cladophoraceae in separate orders & elevated sub families of
Valoniaceae as families of the order.

11. Classification
Divided into 3 families
1.Siphonocladaceae
2.Valoniaceae
3.Anadyomenaceae

12. SIPHONOCLADACEAE
1. Thallus is generally loosely
branched.
2. Lack the small lenticular cells.
3. Segments mature Exogenously.
Eg: Cladophoropsis,
Siphonocladus Cladophoropsis membranacea

13. VALONIACEAE
1. Lack Central axis
2. Lenticular cells are present
3. Segments mature
Exogenously.
Eg: Valonia

14. ANADYOMENACEAE
1.It is closely aligned with
the Cladophorales.
2.Monostromatic thallus.
3.Absence of Segregative
cell division.
4. Isomorphic alternation of generation is seen.
Eg: Anadyomene soldanhae

15. CONCLUSION
The characteristic of Segregative cell division makes
the order Siphonocladales as an unique order which is not
shown by any organisms and there are some confusions in
classifying Siphonocladales into families and subfamilies.

16. References
1. Harold C. Bold & Michael J. Wyne-1978,
Introduction to Algae: Structure & Reproduction
Prentice Hall of India Private Limited, New Delhi
Page number: 211-216
2. Gilbert M. Smith (Stanford University) 2nd Edition -1955,
Cryptogamic Botany Volume I (Algae and Fungi)
McGraw Hill Book Company, INC.
New York Toronto London
Page number: 20, 116-118
3.
https://www.google.co.in/search?q=siphonocladales&biw=1366&bih=667&source=lnms&tbm=isc
h&sa=X&sqi=2&ved=0CAYQ_AUoAWoVChMIzfLU7Z7fyAIVhrCUCh0UBwbK#tbm=isch&q=dicty
osphaeria+cavernosa&imgrc=yiFBpYPBjjiHfM%3A
4. The Japanese Journal of Phycology Vol.30 No.2 , 20 June 1982 Page number: 106-106

17. Thank you