Complex sentence: Individuals were small, a few centimetres tall, and had a simple structure; they lacked leaves, flowers and roots--although it has been speculated that they grew from an unpreserved rhizome.
Split into simpler sentences: Individuals were small, a few centimetres tall, and had a simple structure. They lacked leaves, flowers and roots--although it has been speculated that they grew from an unpreserved rhizome.