Species Profile
Environmental Conservation Online System

Water howellia (Howellia aquatilis)

Kingdom: Plantae
Class: Magnoliopsida
Order: Campanulales
Family: Campanulaceae

Listing Status:   

General Information

Water howellia (Howellia aquatilis) is a winter annual aquatic plant that grows 4-24 inches high. It has extensively branched, submerged or floating stems and narrow, linear, alternate (sometimes opposite) leaves up to 2 inches in length. Water howellia usually flowers in May and June, with small trumpet-shaped blooms ranging from white to light purple in color, at or above the water surface. There may also be small axillary flowers beneath the water surface. Water howellia reproduces only by seed which germinates when ponds dry during fall. This results in annual variability in population size depending on the extent of the previous season’s drying. Flowering occurs from June to August. The plant grows in areas that were once associated with glacial potholes and former river oxbows that flood in the spring, but usually dry at least partially by late summer. It is often found in shallow water (1-2 meters) and on the edges of deep ponds that are partially surrounded by deciduous trees such as black cottonwood and aspen. States in which Howellia aquatilis is known to occur: Currently known from California, Idaho, Montana, and Washington. Historically found in Oregon. The plant has also been found on Turnbull National Wildlife Refuge in Washington.

Lead Region:  Mountain-Prairie Region (Region 6)
Date Listed: Jul 14, 1994

  • States/US Territories in which the Water howellia is known to occur:  California , Idaho , Montana , Oregon , Washington
  • US Counties in which the Water howellia is known to occur:  View All
  • USFWS Refuges in which the Water howellia is known to occur:  RIDGEFIELD NATIONAL WILDLIFE REFUGE , TURNBULL NATIONAL WILDLIFE REFUGE

» Federal Register Documents

Most Recent Federal Register Documents (Showing 3 of 3 )
Date Citation Page Title
04/18/2007 72 FR 19549 19551 Initiation of 5-Year Reviews of Seven Wildlife Species and Two Plant Species in the Mountain-Prairie Region
07/14/1994 59 FR 35860 35864 ETWP; The Plant, Water Howellia (Howellia Aquatilis), Determined to Be a Threatened Species
04/16/1993 58 FR 19795 19800 ETWP; Proposed Listing of Water Howellia (Howellia aquatilis) as Threatened

» Recovery

Recovery Plan Information Search
Current Recovery Plan(s)
Date Title Plan Action Status Plan Status
09/24/1996 Water Howellia (Howellia aquatilis) Recovery Plan, Public and Agency Review Draft View Implementation Progress Draft
Other Recovery Documents (Showing 1 of 1 )
Date Citation Page Title Document Type
04/18/2007 72 FR 19549 19551 Initiation of 5-Year Reviews of Seven Wildlife Species and Two Plant Species in the Mountain-Prairie Region
  • Notice 5-year Review, Initiation
  • » Critical Habitat

    No critical habitat rules have been published for the Water howellia.

    » Conservation Plans

    No conservation plans have been created for Water howellia

    » Petitions

    No petition findings have been published for the Water howellia.

    » Life History

    No Life History information has been entered into this system for this species.

    » Other Resources

    NatureServe Explorer Species Reports -- NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.

    ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.

    Last updated: February 9, 2010