Classification of gymnosperm by chamberlain
- 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 1. CLASS : CYCADOPHYTA 2. CLASS : CONIFEROPHYTA CLASS : CYCADOPHYTA 1. ORDER : CYCADOFILICALES 2. ORDER : BENNETITALES 3. ORDER : CYCADALES CLASS : CONIFEROPHYTA 1. ORDER : CORDAITALES 2. ORDER : GINKGOALES 3. ORDER : CONIFERALES 4. ORDER : 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. 1. CYCADOFILICALES 2. BENNITITALES 3. 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. 1. CORDAITALES 2. GINKGOALES 3. CONIFERALES 4. 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 biloba.
- 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
Editor's Notes
- #13: s