Q.Identify the plant group on the basis of the following feature: Plant body undifferentiated into Root, Stem and leaves.

Algae (Thallophyta) are mostly aquatic organisms with a thalloid body — never differentiated into true root, stem and leaves. Body size ranges from microscopic unicellular forms (Chlorella, Chlamydomonas) to filamentous forms (Spirogyra, Chara) to giant seaweeds tens of metres long (Sargassum). They reproduce vegetatively, asexually and sexually, and show alternation of generations with a dominant haploid phase.

Algae are classified into three classes chiefly by their photosynthetic pigments:

• Chlorophyceae (green algae): mostly freshwater; unicellular/colonial/filamentous; cellulose cell wall; chlorophyll a and b; food stored as true starch; pyrenoids present. E.g. Chlamydomonas, Spirogyra, Chara, Volvox. …