What is a native plant and why does it matter? Part 2

So, last time we left off with marine plants creating enough oxygen to create an ozone layer in the atmosphere. This blocked the UV radiation that made life on land impossible. Algae colonized wet areas on land, followed by primitive plants without roots or vascular systems. All land plants descended from these early colonizers, with some evolving drastically, and others appearing much the same. Freshwater algae, mosses, duckweed, liverworts and club mosses are among the descendants of these early plants that are little changed.

Algaes have often evolved to grow in long strands, but are basically just a bunch of scarcely differentiated cells.