Pinus - Vegetative and reproductive characteristics

1. PHYLUM
CONIFEROPHYTA
Pinus

2. Characteristics
• Big trees with xeromorphic features
• Vascular
o Xylem has no vessels, only tracheid present
o Phloem has no companion cells, but has albuminous cells
• Seed-bearing plants, no fruits
o Naked seeds (no ovary to protect ovule)
• Dominant sporophyte generation (2n)

3. Reproductive Structure: CONES
• Monoecious
o Having both M & F reproductive organs
in the same plant
• Heterosporous
o Producing 2 types of spores
• Megaspore found in megasporangia.
Each scale in cone has 2 megasporangia at
upper surface of the scale in F cone.
• Microspore (pollen grain) produced by
microsporangia. Each scale has 2
microsporangia at the lower surface of
the scale in M cone.
• Pollination by wind
• Fertilization is siphonogamous
o Pollen tubes are developed to fertilize the
F gametes