sentences:  the ascendance of flowering plants over gymnosperms in terrestrial environments.There is evidence that cyanobacteria and multicellular photosynthetic eukaryotes lived in freshwater communities on land as early as 1 billion years ago, and that communities of complex, multicellular photosynthesizing organisms existed on land in the late Precambrian, around .Evidence of the emergence of embryophyte land plants first occurs in the mid-Ordovician (~), and by the middle of the Devonian (~), many of the features recognised in land plants today were present, including roots and leaves.