The variation pattern in the perennialHordeum brachyantherumcomplex and in the annualH. depressumare described. The diploid form ofH. brachyantherums. lat., endemic to California in USA, previously recognized as a separate species is here treated as a subspecies (H. brachyantherumssp.californicum). Despite its restricted distribution it shows a considerable variation and overlap in morphology with the tetraploid ssp.brachyantherum, and no unambiguous determination based on morphology between the two tax a is possible. The tetraploid cytotype has a large distribution area in western North America and easternmost Asia and a very wide morphological variation. It has also a small disjunct distribution area in easternmost Canada. A single hexaploid population from California is referred to ssp.brachyantherum.