1. Heterocysts : Specialised cells found in Nostoc & Anabaena which help in fixation of atmospheric nitrogen.
2. Smallest living cell is Mycoplasma
3. Choanocytes or collar cells – Found in sponges that line the spongocoel & canals.
4. Cnidoblasts/cnidocytes – Found in coelentrata/cnidaria which contain the stinging capsules or nematocytes.
5. Flame cells- Found in flat worms and help in osmoregulation & excretion.
6. Statocysts- These are balancing organs found in arthropods.
7. Root hair- Found in zone of maturation and help in water & mineral absorption.
8. Guard cell- Encloses stomatal aperture or pore. Bean-shaped but in grasses dumb-bell shaped.
9. Subsidiary cells- A few epidermal cells, in the vicinity of the guard cells become specialised in their shape & size & called subsidiary cells
10. Bundle-sheath cells- The vascular bundles are surronded by a layer of thick walled bundle-sheath cells.
