''Isoetes occidentalis'', the western quillwort, is a species of

quillwort ''Isoetes'', commonly known as the quillworts, is the only extant genus of plants in the family Isoetaceae, which is in the class of lycopods. There are currently 192 recognized species, with a cosmopolitan distribution but with the individual s ...

in the family

Isoetaceae Isoetaceae is a family including living quillworts (''Isoetes'') and comparable extinct herbaceous lycopsids (''Tomiostrobus ''Tomiostrobus'' is an extinct quillwort genus from the Early Triassic of Australia, China and Russia, which was espe ...

. It can be found in aquatic habitats of coastal

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...

and

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

south to

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

and

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

. It is frequently found on

Vancouver Island Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest by ...

and around the

Fraser Valley The Fraser Valley is a geographical region in southwestern British Columbia, Canada and northwestern Washington State. It starts just west of Hope in a narrow valley encompassing the Fraser River and ends at the Pacific Ocean stretching from the ...

region. It bears 10 to 30 or more rigid, dark green leaves, each 5 to 20 centimeters long. The velum covers one fourth to one third of the orbicular sporangium, which is 5 to 6 millimeters in diameter. The ligule is shaped like a shortened triangle. The white megaspores are 500 to 700 micrometers in diameter and bear sharp ridges and crests. The microspores are 36 to 43 micrometers long. Though the leaves seem to bear resemblance to those of '' I. lacustris'', especially the occasionally occurring reddish base, ''I. occidentalis'' is a hexaploid and ''I. lacustris'' is a decaploid.

References

occidentalis Flora of Northern America Plants described in 1900 {{Lycophyte-stub