''Isoetes howellii'', or Howell's 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 sp ...

, a type of

lycophyte The lycophytes, when broadly circumscribed, are a vascular plant (tracheophyte) subgroup of the kingdom Plantae. They are sometimes placed in a division Lycopodiophyta or Lycophyta or in a subdivision Lycopodiophytina. They are one of the oldest ...

. It is an

aquatic plant Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

native to North America.

Distribution

Isotes howelii is found in western North America and grows in wet habitats such as

vernal pool Vernal pools, also called vernal ponds or ephemeral pools, are seasonal pools of water that provide habitat for distinctive plants and animals. They are considered to be a distinctive type of wetland usually devoid of fish, and thus allow the safe ...

Description

It produces 5 to 28 pointed, cylindrical, bright green leaves that can reach 30 centimeters in length. The velum covers roughly one third of the spherical

sporangia A sporangium (; from Late Latin, ) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cy ...

, which is 6 millimeters long. The ligule is in the shape of an elongated triangle. The megaspores are 420 to 610 micrometers in diameter. The coarse microspores are 25 to 30 micrometers long. It is closely related to '' I. melanopoda'' and was first thought to be a variation of that species.

References

External links

Jepson Manual TreatmentUSDA Plants ProfilePhoto gallery
howellii Flora of British Columbia Flora of the Western United States {{Lycophyte-stub