Complex sentence: These plants are very simple, lacking an obvious stem or leaves, but consist of a small'thalloid' or plate-like structure that floats on or just under the water surface, with or without simple rootlets.
Split into simpler sentences: These plants are very simple, lacking an obvious stem or leaves. They consist of a small'thalloid' or plate-like structure that floats on or just under the water surface, with or without simple rootlets.