What plants existed in the Precambrian period?

During the Precambrian period, which lasted from about 4.6 billion years ago to 541 million years ago, the Earth was primarily covered by microbial life such as cyanobacteria and algae. These early plants played a crucial role in the Earth's evolution by producing oxygen through photosynthesis, which eventually led to the oxygenation of the atmosphere. Complex multicellular plants did not evolve until much later in the Paleozoic era.