Siegenian

The Siegenian was an epoch of the Devonian period spanning from 411.2 +/- 2.8 To 407 +/- 2.8 Ma. The term overlaps with parts of the internationally recognised Pragian and Emsian epochs, and although once widely used{{cite journal

| author = Niklas, K.J.

| year = 1985

| title = The evolution of tracheid diameter in early vascular plants and its implications on the hydraulic conductance of the primary xylem strand

| journal = Evolution

| volume = 39

| issue = 5

| pages = 1110–1122

| doi = 10.2307/2408738

| publisher = Society for the Study of Evolution

| jstor=2408738

| pmid = 28561493

}} is now deprecated.