CYPERACEAE, SEDGE FAMILY
The Sedge Family is complex. It includes 11 genera and 155 species in Nova Scotia.
More than 70% of these species belong to the Sedge genus, Carex . Almost 90% of the
Sedge family in Nova Scotia is accounted for by four sedge genera: the sedges, spike
rushes, beak rushes and cotton-grasses.
The Sedge Family usually has triangular stems and the leaves have sheaths around stems
that are closed on the side opposite the leaf blade.
The Sedge family includes
1. Various genera that have single or multiple spikes where bisexual flowers (ie. with
male stamens and female pistils) are usually surrounded by bristles and
2. The Sedge genus, Carex, which has unisexual flowers that usually are in separate male
and female spikes (the male spikes are usually uppermost). In some species, some spikes
may have zones of male and zones of female flowers. The fertile, female flowers occur
inside a sac (perigynium) and this produces one seed (an achene). The perigynia are
closely grouped together along short stem branches and these clusters are called spikes.
Each perigynium is underlain by a scale and both are used in identifying species.
DIAGRAMS
A Key to Common and Notable Wetland Sedges, Carex species, in Nova Scotia
1. Spikes of perigynia, one per stem
2. Spikes with all perigynia closely pressed to central axis (ascending and
appressed). Narrow spike has bract at its base
C. leptalea (swamps and wet fields)
2. Spikes with no lower bract and perigynia not appressed to culm axis
3. Perigynia few and reflexed (turned downward) at the base of the spike
C. pauciflora (bogs)
3. Perigynia 15-25 in an oval head C exilis (bogs)
1. More than one spike per flowering stem
4. Terminal staminate spike not obvious (individual staminate
flowers may be present)
5. Individual spikes well separated over the flower stem
6. Spikes on long individual stems
C. pedunculata (floodplains)
6. Not so, spikes sessile (ie. seated directly on central axis)
7. Perigynia few (1-5) per spike
(SECTION HELEONASTES including C. disperma)
8. Lowest spike subtended by a leafy bract that
exceeds the inflorescence C. trisperma (swamps)
8. No such leafy bract. Plants delicate
C. disperma (swamps, openings in swamps)
7. Perigynia 5-15 per spike
9. Plants loose clumps with stolons (overland green
stems) in saltmarsh habitat
C. mackenziei (saltmarsh pondsides)
9. Plants tightly clumped without stolons in
freshwater swamps
10. Perigynia 3-10 per spike, leaves green and
narrow (1-2.5 mm wide)
C. brunnescens (open acid swamps)
10. Perigynia 10-30 per spike, leaves glaucous (2-4
mm wide)
C. canescens (swamps and bogs)
5. Individual spikes overlapping over the length of the stem
11. Spikes appearing star-shaped in outline. Perigynia widely
spreading or reflexed (turned back)
Section STELLULATAE
12. widest leaves 2.8-5mm wide
*C. wiegandii (treed bogs)
12. widest leaves 0.8-2.7 mm wide
C. atlantica (peatlands, sand barrens) and
C. echinata (open peatlands)
(keys to differentiate these are not straightforward or clear)
11. Spikes not star-shaped
13. Spikes with ovoid outline. Perigynia flattened with thin
wings
Section OVALES (separate using hand lens)
14. Perigynia narrow and lance-shaped
15. Main leaves near the top of plant, width
1-3mm
16. Infloresence with a zig-zagging
appearance, spikes not congested
*C. tenera Tender Sedge (vernal pools)
16. Inflorescence short and crowded
17. Spacing between lowest two internodes
= 2-3mm, perigynia about 1 mm wide
C. crawfordii (wet sandy peaty
shores)
17. Spacing = 2-17mm, perigynia about
2mm wide
C. scoparia (moist sandy acidic
soils)
15. Leaves distributed over stem length, 3-7 mm wide
(perigynia loosely spreading, heads not crowded0
C. projecta (swamps, vernal pools)
14. Perigynia widely lance-shaped, more than 2mm wide
(elongate and flexuous inflorescences—slender sedges of saline
habitat)
16. Inflorescence yellow-brown to reddish brown, scales of
perigynia red-brown, lance shaped and some awned
C. hormathodes (saltmarshes)
16. Inflorescences silver-green, scales transparent with gold-green
mid-stripe, scales ovate but acute tipped.
C. silicea (dunes and saltmarshes)
13. Spikes not ovoid or if so, perigynia not flattened or winged
17. Plants delicate
18. Terminal spike with a mixture of staminate and pistillate
flowers
Section ATRATAE: C. buxbaumii (poor fens, scattered,
calcareous wetlands)
18. Not so
C. diandra (fertile marshes, with cattails)
17. Plants coarse
19. Each spike underlain by a bract, stems round
C. vulpinoidea (shores and ditches)
19. A single bract below the lowest spike, stem triangular
C. stipata (common throughout, except peat bogs)
`
4. Terminal spike mostly staminate, narrower than the predominantly pistillate spikes
below
20. Pistilate spikes drooping
21. Pistillate spikes short (<2.5 cm long)
22. Scales protruding beyond the much shorter perigynia
C. magellanica (peatlands)
22. Scales slightly shorter than perigynia
C. limosa (bog and fen pools)
21. Pistillate spikes longer than 2.5 cm
23. Pistillate spikes thin and slender
24. Terminal spike partly pistillate
C. gracillima (wet woods, meadows)
24. Terminal spike all staminate
25. Terminal spike on peduncle above pistillate
spikes, pistillate spikes without lateral stems
C. torta (streams)
25. Terminal spike close to pistillate spikes,
pistillate spikes on peduncles
C. arctata (-----?)
23. Pistillate spikes substantial, not slender
26. perigynia reflexed (turned backward), their beaks
toothed C. pseudo-cyperus (marshes, wet meadows)
26. perigynia not reflexed
27. Not in large clumps, maritime
C. paleacea (head saltmarsh)
27. Large clumps in freshwater wetlands
(open areas of swamps, ditches)
--smooth ventral leaf sheafs =C. crinita
--rough leaf sheaths = C. gynandra
20. Pistillate spikes erect, not drooping
28. Spikes small ovoids or short cylinders (maximum length <2.5 cm)
29. Plants less than 30cm tall, spikes clustered together
Section MONTANAE (*these FACS and FACUS may get
into hummocky swamps, e.g. C. emmonsii var albicans)
29. Plants greater than 30cm tall or not clustered tightly as above
30. Whole plant hairy
C. hirtifolia (floodplains, calcareous meadows)
30. Plant not hairy
31 Leaves inrolled
32. Basal sheath spongy
C. oligosperma (poor fens)
32. Basal sheath hard, sheath tears showing ladder
-like fibres
C. lasiocarpa (lower lake shores, marsh
edges)
31. Leaves not inrolled
33. Perigynia large (7-16mm)
34. Perigynia straw coloured at maturity,
beak of perigynia serrate
35. Leaves 2-4 mm wide, mostly in
Cape Breton
C. michauxiana (mountain
bogs and swamps)
35. Leaves 3-16 mm wide
C. folliculata (swamps
throughout)
34. Perigynia green (particularly the beak),
at maturity, beak smooth
C. intumescens (hardwood swamps)
33. Perigynia smaller ( 2-6 mm long)
36. lowest two pistillate spikes on short stems (pedicels)
C. pallescens (grasslands)
36. all pistillate spikes essentially sessile (not stalked)
37. Spike bur-like, perigynia recurved
C. flava (meadows and wetlands throughout)
37. Spike not bur-like, not as above
C. viridula (varied seaside wet areas)
28. Pistillate spikes are large ovals (> 2.5 cm) or cylinders (>4 cm)
39. Spikes are cylinders with length:width ratio > 2:1
40. Maximum leaf width at least 6 mm, perigynia not flattened, not salt
marsh plants
41. Plants of rich swamps, usually in shade. Leaf edges "scabrous"
(roughened)
C. scabrata (swamps, seeps in woods)
41. Of brackish marshes, estuaries, in the open—not scabrous
C. lacustris (brackish marsh, estuaries)
40. Maximum leaf width less than 6 mm, perignia flattened (except in
saltmarsh plant (C. recta)
42. Plants of saltmarshes, perigynia not flattened
C. recta (heads of saltmarshes)
42. Not of saltmarshes, perigynia flattened:
Section ACUTAE
43. Flowering stems with bladeless sheaths. Lower leaf
sheaths with ladder-like fibres
C. stricta (open peatland and marsh)
43. Flowering stems without conspicuous bladeless sheaths.
No network of fibres on leaf sheaths
44. Staminate spikes two or more, perigynia
nerveless (no veins)
C. aquatilis (swamps to ditches; CB and
northern counties ??)
44. Staminate spike usually solitary, perigynia with
nerves (veins)
45. Leaves overtopping flowering
spikes, plant clumped
C. lenticularis (lakeshores)
45. Leaves mostly not overtopping
inflorescence, plant rhizomatous not
in clumps
C. nigra (wet fields)
39. Pistillate spikes are large ovoids or medium length-fat cylinders
(> 4cm long, length:width less than 2:1)
46. Robust plants with leaves 3-15 mm wide, staminate spikes
overlapping or just above pistillate spikes
47. Plants clumped, no rhizomes; perigynia strongly reflexed
in maturity
C. retrorsa (rich wetlands—not SW NS or near Atlantic
coast)
47. Plants growing from rhizome, not tightly clumped; perigynia
not strongly reflexed
48. perigynia more than 11 mm long, scales without long
narrow tips (awns)
C. lupulina (rich wetland soils)
48. perigynia 6-11 mm long, scales tipped with long awn
C. lurida (margins lakes, marshes; usu. acidic soils)
46. Medium sized sedges, leaves 2-6 mm long, staminate spikes elevated above
and separated from lower pistillate spikes
(Section VESICARIAE In Part)
49. In small clumps usually not in thick vegetation. Pistillate spikes are
short cylinders, spikes with six rows of perigynia
50. Pistillate spikes arched. Perigynia about 5 mm wide
C. tuckermanii (pond margins and vernal pools—rich soils)
50. Pistillate spikes straight. Perigynia 2-3.5 mm wide.
C. vesicaria (lake shores)
49. Often growing among other graminoids. Pistillate spikes more ovoid
than cylindrical, perigynia crowded into eight rows
C. bullata (riparian peatlands of southwestern counties)