Belong to the group Phanerogams i.e., seed bearing plants. They have naked seeds (not enclosed within a fruit). They are mainly xerophytes.
- Have diplontic life cycle.
- Plant body is the sporophyte & the gametophytic generation is very much reduced.
- Sporophyte is well differentiated into root, stem & leaves.
- Roots: Tap root system.
- Stem: Thick, woody with scars of fallen leaves.
- Leaves are 2 types: foliage leaves & scale leaves.
- They are either monoecious or dioecious.
- Secondary growth occurs.
- They are heterosporous and bear male & female cones.
MALE REPRODUCTIVE PART:
- Male cones are smaller in size & short lived.
They consist of spirally arranged microsporophylls.
Microsporophyll bear microsporangia inside which the microspores/pollens are produced after meiosis.
Pollen/microspore starts dividing in the microsporangium.
They produce 1-2 prothallial cells, a generative cell & a tube cell.
Further development occurs after pollination.
The generative cell divides to form body cell & stalk cell. The body cell then produces 2 male gametes. Tube cell forms the pollen tube carrying the male gametes.
Vascular tissue system
- Constitute the vascular bundles.
- Procambial strands of plerome of apical meristem forms the vascular tissue.
- It consists of xylem & phloem.
Xylem(wood) is made of tracheids, vessels, xylem parenchyma & xylem fibres.
Phoem(bast) is made of sieve elements, companion cells, phloem parenchyma & phloem fibres.
- Early formed xylem & phloem are referred as protoxylem & protophloem.
- Later formed are referred as metaxylem & metaphloem.
- Are of 2 types:
Xylem & Phloem form separate bundles present on different radii.
Xylem is exarch i.e., protoxylem towards periphery & metaxylem towards the center.
Found in roots.