identifying features of pinus
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1. Pinus is a large, perennial, evergreen plant.
2. Branches grow spirally and thus the plant gives the appearance of a conical or pyramidal structure.
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3. Sporophytic plant body is differentiated into roots, stem and acicular (needle-like) leaves (Fig. 26).
4. A tap root with few root hair is present but it disappears soon. Later on many lateral roots develop, which help in absorption and fixation.
5. The ultimate branches of these roots are covered by a covering of fungal hyphae called ectotrophic mycorrhiza.
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6. The stem is cylindrical and erect, and remains covered with bark. Branching is monopodial.
7. Two types of branches are present: long shoots and dwarf shoots. These are also known as branches of unlimited and limited growth, respectively.
8. Long shoots contain apical bud and grow indefinitely. Many scaly leaves are present on the long shoot.
9. Dwarf shoots are devoid of any apical bud and thus are limited in their growth. They arise on the long shoot in the axil of scaly leaves.
10. A dwarf shoot (Fig. 27) has two scaly leaves called prophylls, followed by 5-13 cataphylls arranged in 2/5 phyllotaxy, and 1-5 needles.
11. The leaves are of two types, i.e., foliage and scaly.
12. Scaly leaves are thin, brown-coloured and scale like and develop only on long as well as dwarf shoots.
13. Foliage leaves are present at the apex of the dwarf shoots only.
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14. Foliage leaves are large, needle-like, and vary in number from 1 to 5 in different species.
15. A spur (Fig. 28) is called unifoliar if only one leaf is present at the apex of the dwarf shoot, bifoliar if two leaves are present, trifoliar if three leaves are present, and so on.
Some of the species with different types of spurs are as follows:
(i) Pinus monophylla-unifoliar (having only one needle);
(ii) P. sylvestris-bifoliar (having two needles);
(iii) P. gerardiana-trifoliar (having three needles);
(iv) P. quadrifolia-quadrifoliar (having four needles);
(v) P. wallichiana-pentafoliar (having five needles).
2. Branches grow spirally and thus the plant gives the appearance of a conical or pyramidal structure.
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3. Sporophytic plant body is differentiated into roots, stem and acicular (needle-like) leaves (Fig. 26).
4. A tap root with few root hair is present but it disappears soon. Later on many lateral roots develop, which help in absorption and fixation.
5. The ultimate branches of these roots are covered by a covering of fungal hyphae called ectotrophic mycorrhiza.
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6. The stem is cylindrical and erect, and remains covered with bark. Branching is monopodial.
7. Two types of branches are present: long shoots and dwarf shoots. These are also known as branches of unlimited and limited growth, respectively.
8. Long shoots contain apical bud and grow indefinitely. Many scaly leaves are present on the long shoot.
9. Dwarf shoots are devoid of any apical bud and thus are limited in their growth. They arise on the long shoot in the axil of scaly leaves.
10. A dwarf shoot (Fig. 27) has two scaly leaves called prophylls, followed by 5-13 cataphylls arranged in 2/5 phyllotaxy, and 1-5 needles.
11. The leaves are of two types, i.e., foliage and scaly.
12. Scaly leaves are thin, brown-coloured and scale like and develop only on long as well as dwarf shoots.
13. Foliage leaves are present at the apex of the dwarf shoots only.
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14. Foliage leaves are large, needle-like, and vary in number from 1 to 5 in different species.
15. A spur (Fig. 28) is called unifoliar if only one leaf is present at the apex of the dwarf shoot, bifoliar if two leaves are present, trifoliar if three leaves are present, and so on.
Some of the species with different types of spurs are as follows:
(i) Pinus monophylla-unifoliar (having only one needle);
(ii) P. sylvestris-bifoliar (having two needles);
(iii) P. gerardiana-trifoliar (having three needles);
(iv) P. quadrifolia-quadrifoliar (having four needles);
(v) P. wallichiana-pentafoliar (having five needles).
Rachneet:
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The identifying features of Pinus are as follows:
Explanation:
- The Pinus is large evergreen perennial tree.
- The tree branches are conical or pyramidal in structures.
- The Pinus have acicular shaped leaves called as needles.
- The needles are 2 to 8 in number per node.
- The seed cone mature in 2-3 years these are woody and consists of scales with bracts that are spirally arranged.
- The seeds occur in pairs of 2 at the base of cone scale.
- The seeds can be winged or wingless.
Learn more about Pinus:
identifying features of pinus: https://brainly.in/question/1918389
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