Classification of gymnosperm by chamberlain

classification of gymnosperm by chamberlein

1. Classification of gymnosperm by chamberlain M.Sc. PART 1 SONAM YADAV DEPATMENT OF BOTANY PATKAR COLLEGE

2. CONTENT INTRODUCTION CLASSIFICATION CLASS : CYCADOPHYTA CLASS : CONIFEROPHYTA REFRENCE

3. INTRODUCTIONS Gymnosperm are seed bearing vascular plants. Gymnosperm means “ naked seed ”(from the greek : gymnos = naked ; sperm = seed ). The seeds of the gymnosperm lack a protective enclosure (unlike flowering plants which have flowers and fruit). Seeds are produced on the scales of cones . More advanced than ferns because they do not have spores , they have seeds. most of the gymnosperm are trees . All of don’t posses flowers. All gymnosperm have exposed seeds.

4. Classification by chamberlain in (1935)

5. DIVISION : GYMNOSPERM CLASS : CYCADOPHYTA CLASS : CONIFEROPHYTA CLASS : CYCADOPHYTA ORDER : CYCADOFILICALES ORDER : BENNETITALES ORDER : CYCADALES CLASS : CONIFEROPHYTA ORDER : CORDAITALES ORDER : GINKGOALES ORDER : CONIFERALES ORDER : GNETALES

6. CYCADOPHYTA CYCADOFILICALES (PTERIDOSPERMALES) CYCADEOIDALES (BENNETITALES) CYCADALES CONIFEROPHYTA CORDAITALES GINKGOALES CONIFERALES GNETALES

7. CLASS : 1.CYCADOPHYTA It is comparatively small plant with unbranched stem and large fern like leaves . In a transverse section the stem shows large pith and thick cortex. The xylem is manoxylic that is loose and slanty xylem element. It include three order . CYCADOFILICALES BENNITITALES CYCADALES

8. 1.CYCADOFILICALES Cycadofilicales also known as pteridospermales . It is also called as seed fern .They are found only as fossils . Seeds are borne on leaves and never in cones . Example – Lyginopteris .

9. 2.BENNETITALES OR CYCADEODALES The bennetitales were common in mesozoic and were develop in North America. The plant body resemble that of living cycades having stout or slender stem . It is extinct ex – Cycadeoidea .

10. 3.CYCADALES All cycades are xerophytes . The plant are palm like in habit . The stem is short , unbrached and covered with persistent leaf bases. The leaves are pinnately compound and arrange in terminal crown . The cycades are strictly dioecious . That is micro and mega sporophyll develop on separate plants. The ovule are straight that is orthotropous . Example : Cycas .

11. CYCAS PINUS MALE CONES FEMALE CONE OF PINUS

12. CLASS 2 CONIFEROPHYTA This are long profusely branch plants in a transverse section the stem show small pith . The xylem is dense and massive , that is pycnoxylic . Coniferophyta comparises of four order . CORDAITALES GINKGOALES CONIFERALES GNETALES

13. 1 . CORDAITALES Cordaites are extinct and occur as fossil . This are rather tall trees large star shaped leafs and reproductive structure in catkin like cluster structure. Example : Cordaites

14. 2 . GINKGOALES It has been carefully preserved as sacred plant in the temple garden of japan and china . The leaves are broad and bilobed with, dichotomous veining . It is represent by single genus Ginkgo and a single species b iloba .

15. 3 . CONIFERALES Mostely evergreen trees with branch stem. The leaves are needle or scale like, spirally arranged . The leaves posses xerophytic character. Stem shows small pith , thick wood and large number of resin canals . Pollen grain may be winged as in pinus . Sexual reproduction is oogamous . The plant are monoecious ( Pinus ) or dioecious ( Taxus ). The pollination is by wind . Winged seed with the outer thick testa , seed is endospermic . Example : Pinus , Taxus .

16. TAXUS PINUS

17. 4 .GNETALES The plants are xerophytic shrub with dwarf woody stem or woody climber ( liana ). True vessel are present in secondary wood . Opposite leaves, dicotoyledonous embryo. Absence of resin canals . Example : Gnetum .

18. REFeRENCE Gymnosperm by P. C. Vasishta, A. K.sinha,Anil kumar. Gymnosperm structure and Evolution by Chambarlain (1935)

19. Thank you