Ruppia maritima L.
beaked ditch-grass (widgeongrass)
Ruppiaceae (Ditch-grass family)

Introduction to Vascular Plants


© Jamie Fenneman     (Photo ID #7513)


E-Flora BC Static Map

Distribution of Ruppia maritima
Click here to view the full interactive map and legend

Species Information

Perennial, aquatic herb from fibrous roots, rooting at the nodes; stems 30-50 cm long.
Stem leaves threadlike, alternate, 6-12 cm long, 0.2-0.5 mm wide, the tips more or less rounded; stipules membranous, 0.5-2 (7) cm long, fused with the leaves.
Inflorescence on spirally coiled, axillary stalks, the coils 0-3 (4) or lacking, the stalks 3-10 cm long; petals lacking; stamens 2.
Nut-like, egg-shaped, 1.8-2 mm long; beaks terminal, slightly recurved, 0.6-1 mm long.
This is a highly variable species, especially with respect to fruit characteristics. Treatments range from the recognition of only one variable species (including R. occidentalis, e.g., Hitchcock and Cronquist 1973, Dandy 1980) to the recognition of eight or nine varieties (e.g., Scoggan 1978, Brayshaw 1985).

SourceThe Illustrated Flora of British Columbia


If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

USDA Species Characteristics

Flower Colour:
Blooming Period:
Mid Spring
Fruit/Seed characteristics:
Colour: Brown
Present from Spring to Summer
Source:  The USDA


Ecological Framework for Ruppia maritima

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres)
128 0 770
Slope Gradient (%)
0 0 0

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
6 6 8
Modal Nutrient Regime
# of field plots
 species was recorded in:
Modal BEC Zone Class

All BEC Zones (# of stations/zone) species was recorded in

CDF(4), CWH(2), SBS(1)

Habitat and Range

Tidal marshes and brackish ponds, lakes and ditches in the lowland zone; common along the coast; circumpolar, N to AK, disjunctly E to NF and S to ME, MA, PA, NC, FL, TX, ID and CA; Eurasia, S America.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Ruppia maritima var. brevirostris J. Agardh
Ruppia maritima var. exigua Fernald & Wiegand
Ruppia maritima var. intermedia (Thed.) Asch. & Graebn.
Ruppia maritima var. longipes Hagstr.
Ruppia maritima var. maritima
Ruppia maritima var. obliqua (Schur) Asch. & Graebn.
Ruppia maritima var. pacifica H. St. John & Fosberg
Ruppia maritima var. rostrata J. Agardh
Ruppia maritima var. subcapitata Fernald & Wiegand
Ruppia pectinata Rydb.