Grasses, Sedges and Rushes
Browse all grasses Browse all sedges Browse all rushes
What's the difference?
Grasses: the Poaceae family
- Stems jointed, hollow, usually round in cross-section, branched or not
- Sheaths usually open in the front, though edges often overlap
- Leaves 2-ranked (on opposite sides of the stem)
- Flowers usually perfect (both male and female parts)
- Each floret wrapped in 2 bracts/scales
- One seed (grain) per flower
Rushes: the Juncaceae family
- Stems round or compressed in cross-section, not jointed or hollow, branched or not
- Leaves few, mostly basal, round or flat in cross-section
- Sheaths open in front, often auricled
- Flowers perfect, 3 or 6 stamens, 6 tepals
- Capsules with 3 or many seeds
Sedges: the Cyperaceae family
- Stems round or 3-sided in cross-section, not hollow or jointed, not usually branched
- Sheaths usually closed in the front
- Leaves usually 3-ranked (in 3 columns when viewed from the side of the stem)
- Flowers male or female or perfect, each subtended by a single scale/bract
- One seed (achene) per flower
- Achenes lens-shaped or 3-sided, may have bristles or hairs around the base
Subsections follow, or Browse all sedges
Sedges: Carex species
- Stems usually 3-sided, leaves 3-ranked
- Flowers either male or female; spikelets all-male, all-female or mixed
- Florets/achenes enclosed in a sac (perigynium), open only at the tip
- Each perigynium subtended by a single scale; usually spirally arranged
- Achenes lack bristles
Flatsedges, Nutsedges, Umbrella sedges: Cyperus species
- Terminal clusters of multiple spikelets; clusters often round or bottle-brush shaped
- Spikelets usually flattened
- Perfect flowers, 2-ranked (florets on opposite sides of the spikelet stalk)
- Each floret/achene surrounded by a single scale
- Achenes lack bristles
Bulrushes: Scirpus, Schoenoplectus, Bulboschoenus species
- Stems round or 3-sided in cross-section, spongy or firm
- Stem leaves sometimes bladeless or nearly so
- Clusters of few to many, lance-elliptic spikelets, variously arranged
- Leaf-like bracts, or bract appearing as a continuation of the stem
- Perfect flowers, spirally arranged on the spikelet
- Achenes usually with bristles
Spikerushes: Eleocharis species
- Stems round or compressed in cross-section, usually spongy
- Leaves all basal, 2 per stem; lower stem is sheathed
- Single spike at stem tip, usually oval-elliptic; scale-like bracts
- Perfect flowers, spirally arranged on the spike
- Achenes with conspicuous “cap” at tip, usually have bristles
Cottongrasses: Eriophorum species
- Stems round or 3-sided in cross-section
- Stem leaves sometimes bladeless or nearly so
- Terminal cluster of several to many, lance-elliptic spikelets, variously arranged
- Perfect flowers, spirally arranged on the spikelet
- Achenes with long, smooth, white or tawny colored hairs
Other sedges
- Not as above, or other combinations of traits
- Achenes may have bristles
- Includes: Bulbostylis, Cladium, Dulichium, Fimbristylis, Lipocarpha, Rhynchospora, Scleria, Trichophourm species