The Chloroplastida (Land Plants & Green Algae) are perhaps the most obvious representatives of life on earth. They make our planet 'green'. The kingdom includes all trees, flowers, shrubs, herbs and ferns.

Their importance to us (and almost all life) is clear. Most ecosystems on earth ultimately depend on the Chloroplastida for food and energy generated by photosynthesis and carbon-fixation. Our 20% oxygen atmosphere - unique to Earth - was generated by the Chloroplastida billions of years ago. Most earthly life is consequently aerobic (oxygen-dependant).

All Chloroplastida have photosynthesizing chloroplasts with the pigments chlorophyll a and b and often pyrenoid. They all have cell walls nearly always are made of cellulose (wood fiber).

Older terms such as Chlorobiota ('Greenish Life') or Viridiplantae ('Verdant Plants') are no longer relevant. There are many green species outside the Chloroplastida and most Chloroplastida are not exactly 'plants'.