Literally the name chlorophyta or chlorophyceae means green plants. Since the division includes green algae more appropriate term is chlorophycophyta means the green algal plants. Chlorophyceae includes a large no. of species about 6500 under 350 genera. Chlorophyceae are grass – green algae characterised by the following features.
1. Are grass green in colour owing to the presence of chl-a, chl-b carotene, xanthophyll etc.
2. the pigments are localised in green plastids known as chloroplasts.
3. choloroplast contains the pyrenoids
4. The reserve food is starch
5. Well defined nucleus is present.
6. Cell wall contains cellulose.
7. Reproductive structures are motile with 2 and 4 or sometimes a ring of flagella. Flagella are all equal ie isokont flagellation.
8. Sexual reproduction ranging from isogamy to oogamy.
9. Plantbody is unicellular or multicellular. Motile unicellular forms contains eyespot or stigma.
Occurrence :
Most of the chlorophyceae are aquatic. Some are subarial. Green algae comprises about 20000 species. According to Presscott, less than 10% are marine, others are fresh water. Certain orders such as Ulvales and Siphonales are predominantly marine. Orders such as Oedogoniales, Zygnematales are exclusively freshwater. Pleurococcus (Protococcus), Trentopohlia, Protosiphon are subarial seen in tree trunks. Cephaleurose belonging to chaetophorates order, family Trentopohliaceae is parasitic on Coffee and Tea.
Cephaleurose virescens cause the “red rust of tea” in North – East India. Some stains of Chlorella are reported as thermophilic cryophytes are known to occur. Red snow is due to green algae like Raphidonema, Chlamydomonasnivalis etc. The desmid Ancyclonema gives purple or brocon colouration to snow. Many of the freshwater forms occur as planktons. Some are benthoms and few are epiphytes.
