SECTION II. WETLAND PLANT GROUPS
GRAMINOIDS AND THE BIG THREE
Grasses, Rushes and Sedges
Grasses are featured most in Marshes.
Rushes are most common in shoreline ecosystems.
Sedges are the key graminoid of peatlands.
Linear Leaved...is it a Grass, a Rush or a Sedge?
PHOTO: GRASS SEDGE JUNCUS grouped staged
KEY to the BIG THREE: Grass Sedge or Rush
1. Leaves tubular or wiry, rarely grass-like (Juncus marginatus)
Flowers miniature lilies with parts (petals and sepals) in threes
RUSHES = Juncus species
1. Leaves usually grass-like but maybe inrolled in certain sedges
Flower parts are bracts or bristles, flower parts not in threes
2. Leaf sheaths open, stems round in cross-section and hollow, leaves often tworanked
GRASSES = POACEAE
2. Leaf sheaths closed, stems triangular, leaves 3-ranked—usually
SEDGES= CYPERACEAE
RUSHES (JUNCUS species)
The true rushes are part of the Juncaceae Family and we deal here with only the genus
Juncus for the wood rush genus (Luzula) is not a wetland genus. Juncus species are most
common on lake shorelines although there are weedy Juncus in ditches and farm fields as
well as Juncus species in saltmarshes and in peatlands.
LAKE SHORELINES
Lake shores typically house four Juncus species and a lakeshore key follows:
1. Plants tall 40 to 100cm tall
2. Plant usually in deep water with one leaf projecting from then mid point of
flowering stem and surpassing flowers. Plants form a distinctive red/green zone in late
summer. Seeds without white tails....
Military Rush (Juncus militaris)
2. Plants scattered over shoreline with leaves not surpassing inflorescence. Seeds
with tails.....
Canada Rush (Juncus canadensis)
1. Small plants to 50cm tall
3. Stems in a line coming from a linear underground rhizome. Flowers in clusters
of 5-7 ?? produced from the side of stems below the tip
Thread Rush (Juncus filiformis)
3. Stems branching extensively and widely. Flowers in groups of 2-3?? at tips of
branches
Brown-Fruited Rush (Juncus pelocarpus)
PHOTO of LAKE SHORE....of Juncus militaris zone, of Juncus filiformis linear
rhizomes...of J. pelocarpus with bulbils
MARSHES and DITCHES & DRIED OUT WET AREAS
Photo of damp field with Soft Rush ...of ditch with Jointed Rush
1. Tall Plants (maybe more than a metre tall) of dense clumps of soft, dark green "leaves"
(flower stems) with flower clusters borne on the sides of stems just below their tips.
Soft Rush (Juncus effusus)
1. Small plants, mostly less than 50cm tall
2. Tiny annual plants tiny (e.g. 10-15 cm tall), flowers borne over half of the
height of plant
Toad Rush (Juncus bufonius)
2. Perennial plants, 20-50 cm tall, flowers usually borne in the top third of plant
3. Leaves tubular, not flat or merely inrolled
4. Plant stems erect, leaves per stem usually 1-2, seeds with tails
Narrow-Panicled Rush (Juncus
brevicaudatus)
4. Plant stems erect, curved to decumbent and rooting at base,
leaves per stem 3-6. seeds without tails
Jointed Rush (Juncus articulatus)
3. Leaves flat or narrow and inrolled (caution: may appear tubular)
5. Leaves flat (yellow-listed)
Marginal Rush (Juncus marginatus)
5. Leaves narrow and inrolled
6* top of leaf sheath at base of leaf blade prolonged as a
whitish, delicate membrane, an auricle (1-5mm long)
Slender Rush (Juncus tenuis)
6* auricle scant or up to 0.5mm long, may be yellowish and
hard
Dudley's Rush (Juncus dudleyi)
* Degree of difficulty step to differentiate common Juncus tenuis from
rare Juncus dudleyi. Distinction made on auricle alone leading Hines (2000) to
comment that Dudley's Rush is a bit of a dud...as far as auricles go.
PEATLAND RUSHES
Rushes are not well represented in peatlands but there are 4 rushes you should look out
for which with the exception of Caesar's Rush from Cape Breton, are also found in the
previous habitats (e.g. lakes and ditches).
PHOTO of Bog Pool with J canadensis
of marginal zone with rare J caesariensis, of J subcaudatus in spruce swamp
1. Plants small (10-30cm), slender, widely branching. Flowers usually borne as singly
Brown-Fruited Rush (Juncus pelocarpus)
1. Plants mid-size (to 70 cm) to large (to 1m). Flowers in heads of 2-many
2. Leaves rough to touch, seeds at least 2 mm long (Red listed, known Canadian
range is eastern Cape Breton)
Caesar's Rush (Juncus caeariensis)
2. Leaves smooth to touch, seeds less than 2 mm long
3. Capsule not projecting much past the six tepals, white tails of seeds
almost as long as body of seed
Canada Rush (Juncus canadensis)
Canada Rush in stream
from fen (Left) and in a
fen pool (Right)
3. Capsule projects noticeably past the six tepals, tails of seeds only 1/3
length of the seed itself
Woodland Rush (Juncus subcaudatus)
SALTMARSH RUSHES
Saltmarsh plants occur in zones mainly set by the amount of daily immersion in salt
water they receive. There are two ubiquitous saltmarsh rushes and one other which has a
broad salt tolerance, occurring in freshwater and saltwater shores.
1. Inflorescence (flowers) borne from sides of stems, stems borne from linear running
rhizome—usually upper saltmarsh
Baltic Rush (Juncus balticus)
1. Inflorescence terminal
2. Spherical heads of flowers, mainly northeastern counties, wide habitat range
Knotted Rush (Juncus nodosus)
2. Flowers not grouped in compact heads, borne individually. Occurs in large
patches in or adjacent to salthay (Spartina patens) zone in saltmarsh
Black Grass (Juncus gerardii)
PHOTOS...Upper saltmarsh Baltic Rush
Black grass patch in saltmarsh
Black Grass (Juncus gerardii)
patch in salthay zone at Grand Pre