Eleocharis obtusa (Willd.) Schult.
blunt spike-rush (blunt spikerush; egg-shaped spike-rush)
Cyperaceae (Sedge family)

Introduction to Vascular Plants

Photograph

© Jamie Fenneman     (Photo ID #11515)


Map

E-Flora BC Static Map

Distribution of Eleocharis obtusa
Click here to view the full interactive map and legend

Introduction

.

Species Information

General:
Annual (rarely perennial), tufted herb from fibrous roots; stems usually erect, several- to many-ribbed, 5-50 cm tall.
Leaves:
Sheaths firm, blunt; blades lacking.
Flowers:
Spikes solitary, terminal, egg-shaped, (2) 5-13 mm long, many-flowered (rarely less than 40).
Fruits:
Scales 1.7-2.5 mm long, egg-shaped to nearly circular, the lowest ones sometimes empty, purplish or brownish with pale, translucent margins and greenish midribs; perianth bristles mostly 6 or 7, equalling or surpassing the achenes, or reduced or lacking, with fine barbs directed backwards, brownish; stigmas 2 or sometimes 3; achenes lens-shaped, straw-coloured to dark brown, smooth and shiny, (0.8) 1-1.5 mm long including the flattened, broad-based tubercles, which are appressed to the summits of the achenes, 1/2 to as wide as the achenes, and up to 1/2 as long as them.

SourceThe Illustrated Flora of British Columbia

Illustration

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

Ecology

Ecological Framework for Eleocharis obtusa

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

Avg

Min

Max

Elevation (metres)
736 615 805
Slope Gradient (%)
0 0 0

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

0
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
7 6 8
Modal Nutrient Regime
Class
E
# of field plots
 species was recorded in:
3
Modal BEC Zone Class
IDF

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

IDF(2)

Habitat and Range

Marshes, mud flats and wet meadows in the lowland and montane zones; frequent in SW BC, rare in the Queen Charlotte Islands, SC and SE BC; circumpolar, disjunct E to ON, PQ and NS and S to MA, PA, IN, MO and OR; Eurasia.

SourceThe Illustrated Flora of British Columbia

Synonyms

Synonyms and Alternate Names:
Eleocharis diandra var. depressa Fernald
Eleocharis obtusa var. ellipsoidalis Fern. ex Svens.
Eleocharis obtusa var. gigantea (C.B. Clarke) Fern.
Eleocharis obtusa var. jejuna Fern.
Eleocharis obtusa var. obtusa (Willd.) Schult. [superfluous autonym]
Eleocharis obtusa var. peasei Svens.
Eleocharis ovata var. obtusa (Willd.) Kⁿk.
Scirpus obtusus Willd.