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  1. Distribution : It is commonly known as ‘pine’. Six species are found in India (N. East and N. West Himalayas) occurring in wild state. These are :
    1. Pinus gerardiana or Chilgoza pine.
    2. Pinus wallichiana (or P. excelsa) or Blue pine or Kail : Grows upto 3500 metres above sea level.
    3. P. roxburghii (or P. longifolia) or Chir pine.
    4. P. merkusii or Teenasserim pine : Grows upto 600 metres above sea level only.
    5. P. insularis (or P. khasya) or Khasi pine.
    6. P. armandi or Armand’s pine.
  2. Four exotic species of pinus - P. montana, P. laricia and P. sylvestris (Scotch pine) and P. strobus (white pine).
  3. Plant body of pinus is sporophyte and monoecious.
  4. Ectomycorrhiza is present in root of pinus which absorb water, it has Hartig’s network.
  5. Branching of stem is monopodial. Two type of branching-
    1. Long shoots or branches of unlimited growth : Apical buds is present which grows indifinately and bud in the axil has scale leaves.
    2. Dwarf shoots or branches of limited growth : These branches lack apical buds and growth is definate.
  6. Leaves are two types : Scaly and Foliage
  7. The dwarf shoot with needles is called, spur-
    1. One needle - Monofoliar e.g., P. monophylla.
    2. Two needles -Bifoliar e.g, P. merkusi and P.sylvestris.
    3. Three needles - Trifoliar e.g., P.gerardiana and P. roxburghii.
    4. Five needles - Pentafoliar e.g, P. wallichiana.
  8. Secondary growth is present in pinus stem. Wood is pycnoxylic.
  9. Albuminous cells are present in xylem.
  10. Vegetative reproduction is absent in pinus.
  11. Yellow pollen grains are found in pinus (Sulphur shower/yellowish cloud)
  12. Two wings are present on one pollen grain. (Two prothalial cell + One generative cell + One tube cell).
  13. Ovule of pinus has three integuments.
  14. Female gametophyte has 1-8 archegonia, 2-4 neck cells, one ventral canal cell and one egg or oosphere.
  15. Pollination by air (Anemophily).
  16. Micropyle has pollination drop.
  17. Seed formation takes three years.
  18. Embryo of pinus has 9-14 cotyledons.

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