''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
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