ANGIOSPERMS

* the sporophylls are aggeregate to form flowers, angiosperm are also called flowering plant.
*the pollen grain and ovule develops in specialised structure called flower.
*the seeds are enclosed by fruits.
*it has wide range of habitat, except sea because only two species are found there ZOSTERA and THALASSIA
*they range in size from tiny ,almost microscopic WOLFIA to tall tree of EUCALYPTUS
* pollination is through several agencies but most prominent is by insects.
*pollen reach stigmatic surface found at the tip of the carpell.
*female gametophyte develops upto 8 nucleate stage.
*archegonia are absent . instead there is one oosphere surrounded by two synergids that attracts and bring the pollen grains.
*there is double fertilization. one produces embryo,or new sporophyte, the other forms primary endosperm cell.
*endosperm is formed through triple fusion and generally triploid.
*fertilized ovules ripen into seeds. the seeds are covered by fruit. a fruit is technically a ripened ovary.
*xylem contains vessels.
*phloem possessses sieve tubes and companion cells.*secondry growth occurs in stem and root of some angiosperm, placed in group dicots.
*angiosperm are divided  into two sub-groups-
   1. dicotyledonous
   2. monocotyledonous

1. dicot-it is characterised by the presence of two cotyledons in seed,
                generally reticulate venation in leaves,
                concentric tissue in the stem with open vascular bundle arranged in a ring,
                penta or tetramerous flowers.
                e.g.- pea, rose, mulsard, eucalyptus etc

2. monocot- it is characterised by the presence of single cotyledons in seed.
                    generally parallel venetion in leaves
                    scattered closed vascular bundle in stem
                    trimerous flower
                    e.g.- banana, cereals, palms,grasses, bamboo etc.

GYMNOSPERMS

*gymnos means naked and sperma means seed, hence gymnosperm are those plants in which the ovules are not enclosed by any ovary wall.
* it includes medium size trees,tall trees and shrubs.
*SEQUOIA is the tallest tree among gymnosperm.
*it generally posses tap root
*PINUS root has association of fungus called mycorrhiza
*CYCUS root is coralloid and has association with cyanobacteria which helps in nitrogen fixation.
*stem are unbranched in CYCUS and branched in PINUS,CEDRUS.
*leaves may be simple or compound.
*in conifers , the needle like leaf reduce the surface area, their thick cuticle and sunken stomata also      help to reduce water loss.
*gymnosperms are heterosporous, they produce microspore and megaspores.
*spores are produced within sporangia that are borne on sporophylls, which are arranged spirally        along an axis to form lax or compact or strobili or cones. *the cone bearing microsporophylls and microsporangia are called male strobili.
* male strobili produces pollen grain
*the cone bearing megasporophylls and megasporangia are called female strobili.
* in PINUS , male and female cones develops on same tree.
*in CYCUS,male and female cones develops on different tree.
*megaspore mother cell(MMC) differentiate from one of the cell of nucellus, nucellus is protected by ovule, the ovule clustered to form female cone. this MMC develops 4 megasporangium one of which develops into multicellular female gametophyte bear two or more archegonia or female sex organ.
* male and female gametophyte do not have free living existance, they remain wthin sporangia.
*after fertilization zygote develops into an embryo and the ovules into seeds, seeds are not covered.

CYCAS

PINUS

GINKGO