Coniferophyta the Devonian division includes seeds

 Coniferophyta the Devonian division includes seeds

Coniferophyta The division Coniferophyta includes many fossils and living forms. The members of Coniferophyta are characterised by tree-like habit with many branches, simple leaves, pycnoxylic wood and bilaterally symmetrical seeds. The division Coniferophyta is divided into 4 orders : Cordaitales, Coniferales, Ginkgoales, Gnetales Order : 

Cordaitales : The order consists of extinct plants, which were originated in the Devonian period. The plants were tall trees with crown of branches. The secondary growth in stem is pycnoxylic. The leaves were xerophytic and dichotomously branched. The male and female strobili occurred on the same plant. (monoecious) There were few ovules in a strobilus. The male sporophyll bears 6 pollen sacs. Eg. Pitys, Cordaites and Mesoxylon.

Order : Coniferales : It is the largest order of gymnosperms. They originated in the Carboniferous period. They include three-fourth of the living gymnosperms. The plants are long, branched and evergreen trees. The branches axe dimorphic, ie. with long and dwarf shoots. The leaves are needle-like. The wood is pycnoxylic.

 Resin canals occur in roots, stems and leaves. The plants are dioecious or monoecious. The micro and megasporophyll form compact male and female cones respectively. The male cones are small and are formed in groups. The female cones are larger and perennial. 

The megasporophyll differentiated into a bract scale and ovuliferous scale. The fertilization is siphonogamous. The male gametes are non-motile. Eg. Pinus, Araucaria, Thuja, Podocarpus, Taxus.