How Do Plants Absorb Water If They Have No Roots?
Background The most prevalent plant species on Earth take up water from soil through a system of roots. Two exceptions to this are nonvascular plants and epiphytes, which either absorb rain water or sap humidity directly from the air. Due to these and other limitations, neither has ever been a prominent species on the planet. Non-Vascular Plants Non-vascular plants are those lacking a vascular system, the xylem (or “woody” tissue) and phloem (tissue that transports and distributes nutrients and water throughout the plant); they are without roots, leaves or stems, though several contain other specialized tissues that convey water within the plant. The three categories of nonvascular plants are Bryophyta (around 10,000 species, including mosses and lichens), Hepatophyta (roughly 6,500 species of liverworts) and Anthocerophyta (100 or so species of hornworts). Although mosses and lichens lack true roots, they have rhizoids, with which they attach themselves to plants and rocks that act as
