Title: Plant - Definition of the kingdom | Britannica
Headings: Definition of the kingdom
Definition of the kingdom
See how evolution in plants, from bryophytes to angiosperms, has provided habitats and food sources for organisms
Nonvascular plants
Definition of the category
Compare and contrast reproduction, water absorption, and energy generation of liverworts and mosses

Content: others have become adapted to alternately wet and dry environments by growing during wet periods and becoming dormant during dry intervals. Although bryophytes are widely distributed, occurring in practically all parts of the world, none are found in salt water. Ecologically, some mosses are considered pioneer plants because they can invade bare areas. Bryophytes are typically land plants but seldom attain a height of more than a few centimetres. They possess the photosynthetic pigment chlorophyll (both a and b forms) and carotenoids in cell organelles called chloroplasts. The life histories of these plants show a well-defined alternation of generations, with the independent and free-living gametophyte as the dominant photosynthetic phase in the life cycle. ( This is in contrast to the vascular plants, in which the dominant photosynthetic phase is the sporophyte .) The sporophyte generation develops from, and is almost entirely parasitic on, the gametophyte. The gametophyte produces multicellular sex organs ( gametangia ). Female gametangia are called archegonia;