1.3.Fossil Gymnosperms B.Sc I Sem II SGBAU

Paleobotany

1. UNIT -I
1.3 FOSSIL
GYMNOSPERMS
Prof. Pranav V Gadkar,
M.ScNET-JRF, SET, GATE
Assistant Professor,
Department of Botany,
BNB College Digras.

2. PlantFossilsfrompaleozoicera–paleobotanistcalledthemas
progymnosperms
Progymnosperms-Nearertogymnospermsbutnotcompletegymnosperms
Constitutedmostoftheworlddominantvegetationthroughoutpaleozoic
andmesozoicdeclinedthereafter.
Prof. P. V. Gadkar, BNB College, Digras

3. Geological History of Gymnosperms
Prof. P. V. Gadkar, BNB College, Digras

4. Knownas‘SeedFerns’.
Groupisfrompaleozoicera.
Showaffinitieswithpteridophytesandgymnosperms
Slenderstemwithlargefrondlikeleaves
Medullatedprotostelewithmesarchprimaryxylem
Ovulesborneonpinnatelycompoundmegasporophyllnotarrangein
strobilli
Microsporophyllarepinnatelycompoundandnotinstrobilli
Prof. P. V. Gadkar, BNB College, Digras

5. Arnold(1948)dividedcycadofilicalesintofollowing3families-
1.Lyginopteridaceae-eg.Lyginopteris,Heterangium
2.Medullosaceae-eg.Medullosa
3.Calamopityaceae-eg.Calamopitys
Sporne(1974)dividedpteridospermalesinto7families
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. BestknownfossilinCarboniferousperiod
Roots,Stem,Leavesandseedsofthisplantwereindependentlystudiedbybotanist
Afterdetailstudyfinallyrealizedthatthesewereallpartsofsingleplantvarious
partsdiscoveredwerenamedasunder.
Leaves -Sphenopterishoeninghausii
Stems -Lyginopterisoldhamia
Petioles -Rachiopterisaspera
Roots- -Kaloxylonhookeri
MaleReproductivestructure-Crossothecahoeninghaussi
Seeds -Lagenostemalomaxii
Prof. P. V. Gadkar, BNB College, Digras

8. •Presenceofcapitategland
oncupulateenvelope
enclosingseed
•Alsoreportedonstem,
leavesandalsoonrachisand
becomesthebasisfor
constructionofplant
Lyginopterisoldhamia
Prof. P. V. Gadkar, BNB College, Digras

9. Morphology:
Climber,Stemlong&aerial
Proprootspresentfor
support
Leavesmanyspirally
arranged&bipinnateor
tripinnate
Rachis&petiolewerefixed
withcapitategland
Reconstructed plant of Lyginopterisoldhamia
Prof. P. V. Gadkar, BNB College, Digras

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

11. Eustelei.e.conjoint,collateral&openvascular
bundlewithcentralpithshowspresenceof
sclerenchymatouscell
PrimaryXylemMesarch
Secondorygrowthbycambium&Secondory
xylemformedoccupiedmajorpart
Monoxylicsecondoryxylem
BetweenPriandsecxylemleaftracesseen
Extrastellarregionconsistofcortex
Outercortexshowsschleroticnests
Prof. P. V. Gadkar, BNB College, Digras

12. 2. Root ( Kaloxylonhookeri) :
Namedaskaloxylonhookeri
Adventitioustype
Diameter7mm
Producelateralroots
T.s.showepidermaloutlinewhere
epidermalcellgetcrushed
Broadcortexdivisibleintoouter
andinner
Outercortexcomparedwith
velamen
Steletetrachtooctarch
Phloemalternatewithxylem
Endodermis&pericyclesingle
layered
Prof. P. V. Gadkar, BNB College, Digras

13. Designatedassphenopteris
hoeninghausii
Consideredasleafoflyginopterisonthe
basisofcupulategland
Leavesarearrangedin2/5phyllotay
Frondisbranched,branchingeither
dichotomousortrichotomous.
Onultimatebranchespinules
developed
Leafshowslongrachis
Prof. P. V. Gadkar, BNB College, Digras

14. Epidermiscutinisedonadaxialsurface
Stomataonlyonabaxial
SingleV.B.aretherecomprisingxylemandphloem‘V’shaped
Leaftracesdevelopedfromrachisentersintopith.
Prof. P. V. Gadkar, BNB College, Digras

15. PlantHeterosporous
Ovulesandseedswereenclosed
withinprotectivecupules
ImpressionofCrossothecawas
foundinconnectionwithleaves&
ConcludedasMicrosporangium
Theovulesandseedsdescribed
undernameLagenostomalomaxi
Prof. P. V. Gadkar, BNB College, Digras

16. ConsistofFlatteneddistalpinules
6-7bilocularpendantmicrosporangia
presentonpeltatefertilepinnulecalled
microsporophylls
Microsporangiumwasabout3mmin
length&dehiscencewaslongitudinal
Microsporespresentincavitiesof
microsporangia
Microsporehadthickroughexine&shed
aftermaturity
Oneormoreorganshowsaffinitywith
lyginopteridaceaereferredasTellangium,
Tellangiopsis,Faraxotheca
Prof. P. V. Gadkar, BNB College, Digras

17. Seedwithsmall,barrelshaped5-6mm
Seedsurroundedbycupulepresentattheendofslenderrachis
Rachiscoveredbyglands&hairs
Orthotropousovule
Prof. P. V. Gadkar, BNB College, Digras

18. TheNucelluswasfreeattip
Laterstagessurroundedbybellshapedchamberor‘lagenostome’.
Theovulesurroundedbyouterhardstonylayerandinnerfleshylayer
Capitateglandsalloverovule
Prof. P. V. Gadkar, BNB College, Digras

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

20. ReportedfromupperJurassictoupper
cretaceous
Occursinformofpetrifaction
Trunkswereshort,sphericaltosub
spherical
Showsresemblancewithlivingcycads
Attaindiameterabout50cm&persistent
leafbases
Compactcrownoflargepinnately
compoundleavespresent
Leafletshadparallelveins
Prof. P. V. Gadkar, BNB College, Digras

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

22. Reproductiveorganscalledflowers
Flowerbudspresentinaxialofleaves
Flowersbisexualdevelopedonpedicel
Surroundedbymanybracts
Whorlofstamenwasabovethebract
Stamenwaspinnatelybranched&eachpinnaehasdouble
rowofpurseshapedsporangia
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