Brachyelytrum is a small grass

Grass

Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

 genus that occurs in eastern North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and eastern Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

. It is one of several grass species that displays this classic floristic disjunction pattern. There are three species recognized currently in Brachyelytrum: B. aristosum (distributed in southeastern Canada and the northeastern USA), B. erectum (distributed in the northeastern USA and adjacent southern Canada), and B. japonicum (distributed in Japan and southeastern China).

Recent molecular phylogenetic study has indicated that, within the grass family (Poaceae

Poaceae

The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...

) Brachyleytrum is the sister-group of the subfamily Pooideae

Pooideae

The Pooideae is a subfamily of the true grass family Poaceae. It includes some major cereals such as wheat, barley, oat, rye and many lawn and pasture grasses.- List :...

(the cool season grasses), a lineage that includes many of the world's major cereal crops such as barley, wheat, and oats.