Question

The two layers of teeth in peristome of a moss are

• A. Parts which help in the gradual dispersal of spores, the upper teeth are hygroscopic and open out only in dry weather. The lower one check sudden dispersal.
• B. Decorative parts functioning like sepals and petals in a flower.
• C. Parts which help in the discharge of spores only when the capsule matures. After the operculum falls they dry up and open out.
• D. Parts which help in the dispersal of spores. They are not hygroscopic and allows the discharge of spore disintegration of capsule wall.

Answer 1

The correct option is A Parts which help in the gradual dispersal of spores, the upper teeth are hygroscopic and open out only in dry weather. The lower one check sudden dispersal.

Peristome (exposed) plays an important role in the dispersal of spores. The peristome teeth by their hygroscopic movements help in the discharge of the spores. The inner peristome simply functions as a sieve. The spores are liberated in the dry weather and are carried out by air.