Learn how to say Stonewort correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word stonewort:
a freshwater plant with whorls of slender leaves, related to green algae. Many kinds become encrusted with chalky deposits, giving them a stony feel.
Chara and other genera in the class Charophyceae, division Chlorophyta; sometimes placed in its own division (Charophyta)