Algae

Algae belongs to division Thallophyta. algae grow in marine or fresh water. Most of them are free-living while some are symbiotic.

i. Habitat: Algae are mostly aquatic, few grow on other plants as epiphytes and some grow symbiotically. Some algae are epizoic ie, growing or living non-parasitically on the exterior of living organisms.

ii. Aquatic Structure: Plant body is thalloid i.e. undifferentiated into root, stem and leaves. They may be small, unicellular, microscopic like Chlorella (non-motile), Chlamydomonas (motile). They can he multicellular, unbranched, filamentous like Spirogyra or branched and filamentous like Chara. Sargassum is a huge

iii. macroscopic sea weed which measures more than 60 meters in length. Cell wall: The algal cell wall contains either polysaccharides like cellulose / glucose or a variety of proteins or both.

iv. Reserve food material: Reserve food is in the form of starch and its other forms, Photosynthetic pigments: Photosynthetic pigments like chlorophyll a, chlorophyll b, chlorophyll - e, chlorophyll-d, carotenes, xanthophylls, phycobilins are found in algae. 

v. Reproduction: Reproduction takes place by vegetative, asexual and sexual method.

vi. Life cycle: The life cycle shows phenomenon of alteration of generation, dominant haploid and reduced diploid phases.