Definition: Gymnosperms are seed-bearing plants with NAKED seeds — not enclosed in a fruit. "Gymnosperm" = Greek gymnos (naked) + sperma (seed).
Key Features:
- Seeds borne on megasporophylls (often organised into cones)
- Wind pollination (anemophily)
- Pollen tube formed → no water needed for fertilization (major advance)
- Non-flagellate sperm (in Pinus) OR multiflagellate sperm retained (in Cycas, Ginkgo — primitive feature)
- No flowers, no fruits
- Sporophyte dominant, gametophyte microscopic (few cells)
- Secondary growth present (vascular cambium)
Critical Examples for NEET:
| Species | Key Features |
|---|---|
| Pinus | Needle leaves (xerophytic), monoecious (same plant), resin canals, most common gymnosperm in NEET |
| Cycas | Dioecious (separate plants), largest ovules in plant kingdom, living fossil, motile (multiflagellate) sperm retained, palm-like |
| Ginkgo biloba | Living fossil, fan-shaped deciduous leaves, dioecious, motile sperm, only surviving species of Ginkgophyta |
| Sequoia sempervirens | Tallest living tree (>115 m), coastal redwood, gymnosperm |
NEET Must-Know:
- Pinus = monoecious ≠ Cycas (dioecious)
- Gymnosperms ≠ Double fertilization (only angiosperms have double fertilization)
- Gymnosperms = Seeds YES, Fruits NO, Flowers NO
- Largest ovules = Cycas (not any angiosperm)