Paleobotany

1. UNIT - I
1.3 FOSSIL
GYMNOSPERMS
Prof. PranavV Gadkar,
M.Sc NET-JRF,SET, GATE
Assistant Professor,
Department of Botany,
BNB College Digras.

2.  Plant Fossils from paleozoic era – paleobotanist called them as
progymnosperms
 Progymnosperms-Nearer togymnospermsbutnotcompletegymnosperms
 Constituted most of the world dominant vegetation throughout paleozoic
andmesozoicdeclinedthereafter.
Prof.P. V. Gadkar, BNB College,Digras

3. GeologicalHistoryofGymnosperms
Prof.P. V. Gadkar, BNB College,Digras

4.  Knownas‘SeedFerns’.
 Groupisfrompaleozoicera.
 Showaffinitieswithpteridophytesandgymnosperms
 Slenderstemwithlargefrondlikeleaves
 Medullatedprotostelewithmesarchprimaryxylem
 Ovules borne on pinnately compound megasporophyll not arrange in
strobilli
 Microsporophyllare pinnatelycompoundandnotinstrobilli
Prof.P. V. Gadkar, BNB College,Digras

5.  Arnold(1948)dividedcycadofilicalesintofollowing 3families-
1. Lyginopteridaceae-eg. Lyginopteris,Heterangium
2. Medullosaceae- eg.Medullosa
3. Calamopityaceae-eg. Calamopitys
 Sporne(1974)dividedpteridospermalesinto 7families
1. Lyginopteridaceae
2. Medullosaceae
3. Calamopityaceae
4. Glossopteridaceae
5. Peltaspermaceae
6. Corystospermaceae
7. Caytoniaceae
Prof.P. V. Gadkar, BNB College,Digras

6. Systematic Position
Sub dividion- Cycadopsida
Order- Pteridospermales
Family- Lyginopteridaceae
Genus- Lyginopteris
Species- oldhamia
Prof.P. V. Gadkar, BNB College,Digras

7.  Best known fossil in Carboniferous period
 Roots, Stem, Leavesand seeds of this plant were independently studied by botanist
 After detail study finally realized that these were all parts of single plant various
parts discovered were named as under.
Leaves -Sphenopteris hoeninghausii
Stems -Lyginopteris oldhamia
Petioles -Rachiopterisaspera
Roots- -Kaloxylonhookeri
Male Reproductive structure -Crossotheca hoeninghaussi
Seeds -Lagenostemalomaxii
Prof.P. V. Gadkar, BNB College,Digras

8. •Presence of capitate gland
on cupulate envelope
enclosing seed
•Also reported on stem,
leaves and also on rachis and
becomes the basis for
construction of plant
Lyginopteris oldhamia
Prof.P. V. Gadkar, BNB College,Digras

9. Morphology :
 Climber, Stem long & aerial
 Prop roots present for
support
 Leaves many spirally
arranged & bipinnate or
tripinnate
 Rachis & petiole were fixed
with capitate gland
ReconstructedplantofLyginopterisoldhamia
Prof.P. V. Gadkar, BNB College,Digras

10. 1. Stem:(Lyginopteris oldhamia)
T.S.of Mature Stem
Prof.P. V. Gadkar, BNB College,Digras

11. Eustele i.e. conjoint , collateral & open vascular
bundle with central pith shows presence of
sclerenchymatous cell
PrimaryXylem Mesarch
Secondory growth by cambium & Secondory
xylem formed occupied major part
Monoxylic secondory xylem
Between Pri and sec xylemleaf traces seen
Extrastellar region consist of cortex
Outer cortexshows schlerotic nests
Prof.P. V. Gadkar, BNB College,Digras

12. 2. Root ( Kaloxylonhookeri) :
Namedaskaloxylonhookeri
Adventitioustype
Diameter7 mm
Producelateralroots
T.s. show epidermal outline where
epidermal cell getcrushed
Broad cortex divisible into outer
andinner
Outer cortex compared with
velamen
Steletetrachtooctarch
Phloem alternatewithxylem
Endodermis & pericycle single
layered
Prof.P. V. Gadkar, BNB College,Digras

13. Designated as sphenopteris
hoeninghausii
Considered as leaf of lyginopteris on the
basis of cupulate gland
Leaves arearrangedin 2/5 phyllotay
Frond is branched , branching either
dichotomous ortrichotomous.
On ultimate branches pinules
developed
Leaf shows long rachis
Prof.P. V. Gadkar, BNB College,Digras

14. Epidermis cutinised on adaxialsurface
Stomata only on abaxial
Single V.B. are there comprising xylemand phloem ‘V’ shaped
Leaf traces developed from rachisenters into pith.
Prof.P. V. Gadkar, BNB College,Digras

15. Plant Heterosporous
Ovules and seeds were enclosed
within protective cupules
Impression of Crossotheca was
found in connection with leaves &
Concluded asMicrosporangium
The ovules and seeds described
under nameLagenostoma lomaxi
Prof.P. V. Gadkar, BNB College,Digras

16. Consist of Flattened distal pinules
6-7 bilocular pendant microsporangia
present on peltate fertile pinnule called
microsporophylls
Microsporangium was about 3mm in
length &dehiscence was longitudinal
Microspores present in cavities of
microsporangia
Microspore had thick roughexine &shed
after maturity
One or more organ shows affinity with
lyginopteridaceae referred as Tellangium,
Tellangiopsis, Faraxotheca
Prof.P. V. Gadkar, BNB College,Digras

17. Seedwith small ,barrel shaped 5-6mm
Seedsurrounded by cupule present at the endof slenderrachis
Rachis coveredby glands &hairs
Orthotropous ovule
Prof.P. V. Gadkar, BNB College,Digras

18. TheNucellus was free at tip
Later stages surrounded by bell shaped chamberor ‘lagenostome’.
Theovule surrounded by outer hard stony layer andinner fleshy layer
Capitate glands all overovule
Prof.P. V. Gadkar, BNB College,Digras

19.  Systematicposition
Subdivision–Cycadopsida
Order–Bennettitales
Family–Bennettitaceae
Genus- Bennettites
Prof.P. V. Gadkar, BNB College,Digras

20. Reported from upper Jurassic to upper
cretaceous
Occursin form of petrifaction
Trunks were short, spherical to sub
spherical
Shows resemblancewith living cycads
Attain diameter about 50 cm& persistent
leaf bases
Compact crown of large pinnately
compound leaves present
Leaflets had parallel veins
Prof.P. V. Gadkar, BNB College,Digras

21.  T.S. ofStem
Prof.P. V. Gadkar, BNB College,Digras

22.  Reproductive organs called flowers
 Flower buds present in axial of leaves
 Flowers bisexual developed on pedicel
 Surrounded by many bracts
 Whorl of stamenwas above thebract
 Stamen was pinnately branched & each pinnae has double
row of purse shaped sporangia
Prof.P. V. Gadkar, BNB College,Digras

23. Prof.P. V. Gadkar, BNB College,Digras

24. Prof.P. V. Gadkar, BNB College,Digras

25. Prof.P. V. Gadkar, BNB College,Digras

26. Prof.P. V. Gadkar, BNB College,Digras