Caytoniales and pentoxylales

1. GOVT. SUKHRAM NAGE COLLEGE NAGRI
DHAMTARI (C.G.) 493778
Session – 2023-24
Paper 4 – Bryophyta, Pteridophyta and Gymnosperm
Topic - CAYTONIALES AND PENTOXYLALES
. Date - 29 - 09 - 2023
Guided by
Asst. Prof. L. Rathiya
Presented by
Chelsi Dewangan
M. Sc. 1st sem Botany

2. CONTENT
Caytoniales
• Introduction
• History
• Leaves- Sagenopteris
• Megasporophyll – Caytonia
• Microsporophyll – Caytonanthus
• Pollen grains
Pentoxylales
• Introduction
• History
• Morphology
• Anatomy
• Stem genera
• Leaves
• Seed beating organ
• Pollen bearing organ

3. INTRODUCTION
Fossil Gymnosperms
Family- Caytoniaceae
• Small branched trees or shrubs.
• Have leaves , seed bearing organ,
male and female cones.
Fig. Caytoniales
Caytoniales

4. HISTORY
• First describe by Hamshaw Thomas 1925.
• Middle Jurassic rocks in Yorkshire coast of England.

5. Leaves - Sagenopteris
• Middle Jurassic of Yorkshire
1. S. Colpodes
2. S. Philipsi
• Basal lias of Greenland
1. S. Nilssoniana
• Palmately compound.
• Consist petiole , 4 terminal leaflets,
2- 6 cm length .
• Prominent midrib , reticulate venation.
• Two pairs not whorl.

6. • Formation of abscission – whole leaf falls ( angiosperms character) .
• Leaflets cover by epidermis.
• Stomata present in lower surface.
• Two guard cells. ( independent origin) .

7. Megasporophyll- Caytonia
• Two fruit genera described by Thomas (1925).
• Caytonia sewardii
• Caytonia nathorsti
• Caytonia consist of rachis about 5cm length.
• Petioles.
• Swollen at tips like berries.
• These outgrowth called fruits by Harris.
• Juicy bulb surrounding the seed ( cupul ).
• The megasporophyll is pinnate structure and not
fruiting axis, bearing berries with ovaries.

8. Microsporophyll - Caytonanthus
• Described by Phillips (1829) Form yorkshire.
• Three species known
1. C. arberi ( Tomas ) Harris.
2. C. oncodes , Harris
3. C. kochi , Harris.
• Central axis is dorsiventral.
• The pinnae are opposite and branched
irregularly.
• Each branchlet bears tetra loculat synangium.
• The 4 sporangia or pollen sac seprate out
except the tip after dehiscence.

9. Pollen grains
• The pollen grains are unicellular and
winges.
• Two wings , opposite to each other.
• Grove found almost every pollen grains.
• Pollen grains covered by distinctly
cutinized wall.
• Pollen grains tetrad
• 25-35 micromiter.
• Its sporoderm 2 layered
1. Outer – alveolate
2. Inner – thick lamellate.

10. INTRODUCTION
• Fossil gymnosperms
• Stem – pentoxylon , niponioxylon.
• Leaves – Nepaniophyllum.
• Pollen bearing organs – Sahnia
• Seed bearing organs – Carnoconites.
Pentoxylales

11. HISTORY
• Pentoxyleae was proposed by Prof. Birbal
Sahni (1948).
• Fossil plants from Jurassic period.
• The Rajmahal hills ( Bihar) of India.
• Sahni and Srivastav ( 1948) Researches
on the Stem , leaves and seed bearing
organ .
• Vishnu Mittre described pollen bearing
organ in 1953
Prof. Birbal Sahni

12. MORPHOLOGY
• The plants shrubs or small trees.
• Two types of branches –
1. Long shoots
2. Dwarf shoot
• The stem were 3mm to 2 cm long.
• Spirally arranged leaves.
• Leaves were simple ,and thick.
• Venation open , rarely reticulate.

13. ANATOMY
• The stem were polystelic with 5
primary steles, hence the name
pentoxylae.
• Each stele has complete ring of
cambium.
• The development of secondary
wood Become exocentric.
Fig. T. S. Of stele

14. STEM GENERA OF PENTOXYLALES
• Pentoxylon SAHNII and Niponioxylon guptai are
the stem genera of pentoxyleae.
1. PENTOXYLON SAHNII
• 3mm to 2 cm diameter.
• presence of 5 steles .
• short lateral shoot arose from the stem.
• Descovered from Raj Mahal hills in India.

15. 2. NIPONIOXYLON
• Discovered from the village
Nipania and hence named
Nipanioxylon.
• Difference – larger number
of bundles ( stele) .
• Less developed secondary
growth in the stem.

16. Leaves of pentoxylales
NIPANIOPHYLLUM
• Nipaniophyllum raoi.
• They were present on the
short lateral shoot.
• Leaf was simple, petiolate ,
strap- shaped and possessed a
well developed mid – rib with
many parallel lateral veins.

17. Seed bearing organ
CARNOCONITES
• female cones
• Two species - ( C. campactum , C. Laxum. )
have been described by Sahni and Srivastav
from Jurassic horizon of Rajmahal hills.
• Not found in organic connections but occur
in some rocks.
• Terminal on short lateral shoot and looked
like stalked mulberry fruit.
• 1 . 8 cm long
• Attached about 20 sessile ovules.
• C. Laxum 3cm long , 5 mm in diameter.

18. Pollen bearing organ
• SAHNIA NIPANIENSIS
• male flower or male organ discribed by Vishnu Mittre
(1953) .
• Present terminally on the shoot and fused basally in a
shallow disc.
• Each male flowers consisted of a dome – shaped receptacle.
• 24 microsporangiophore arranged around it in a single
whorl.
• Sporangiophore branched , this branched pear- shaped.
• The sporangiophore unilocular and contains boat shaped
pollen grains.

19. Thankyou