Tsaia denticulata is one of the primitive vascular plants (Trimerophytes) that lack roots and leaves while the branching stems were photosynthetic throughout their length.
Tsaia denticulata Wang et Berry
Middle Devonian, Yunnan, China
Size: 12x10cm
Lycophytes - Club Mosses
They developed leaves that contained vascular tissue and appeared during the Early Devonian. They are the oldest group of vascular plants that still exist today as tiny club mosses. However, in the Carboniferous some Lycophytes, such as Lepidodendron were forest-forming trees more than 30 metres tall.
Sphenophyta - Horsetails
The horsetails arose in the Late Devonian and are represented today by the genus Equisetum. The group is defined by their jointed stems with many extremely small non-photosynthetic leaves being produced at a nodes. Extinct members include tree-like plants, which were a prominent part of the Carboniferous swamp-forests, some of them, Calamites, growing more than 20 metres tall.
