Sedge Group 4
What are they?
This group includes sedge species that have their flowers arranged in several spikelets, with the upper spikelets made up of all (or mostly all) male and the lower spikelets made up of all female flowers. There is thus a clear different between the upper and lower spikelets. The hairless utricles in members of this group separates them from Group 3 sedges, while the female flowers with two stigmas separates them from groups 5 and 6 sedges.
Where are they found?
These are mostly sedges of wetland habitats, though one species occurs as an introduction or escape from cultivation.
Identification
While the overall flower spike details define this group, the finer details of the flowers and fruits are necessary for species identification. Note the shape and colour of both the male and female glumes (flower bracts) and note details of shape and size of the ripe utricles (fruits). It can also be useful to note whether the plant is tussock forming or grows in spreading colonies of stems and also to note the shape of the leaf ligule - the membranous line where the leaf blade meets the stem.
Lesser Pond Sedge Carex acutiformis
Native. Widespread and common along rivers, larger ditches and channels and beside ponds, lakes and broads. Will often grow in shady conditions in alder and willow carr and other wet woods. Flowers June to July, fruits July to September. Plants form extensive spreading colonies (sedge beds), 60-150cm in height. Leaves 7-10mm wide, with a pointed ligule. Flower spike about one third the length of the stem, with 2-3 male and 3-4 female spikelets. male glumes obtuse to subacute at the tip; female glumes acute. Flowers usually with three stigmas but occasionally with two. Utricles 3.5-5mm long, elliptical to oval, flattened, with beak 0.5mm long and slightly notched at the tip.
Often grows together with Greater Pond Sedge, from which it is most easily told by the shape of the tips of the glumes (if in flower) or by the shape of the leaf ligule.
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Common Tufted Sedge Carex elata
Native. A rather local species but can be common where it occurs and East Anglia is a National stronghold. Favours seasonally flooded ground and wet areas along larger rivers and in fens. Flowers May to June, fruits June to July. Plants form dense tussocks, to 40cm in height. Leaves 3-6mm wide, up to 100cm long and arching, mid-green above, blue-green beneath; old leaves fraying into reticulate fibres. Flower spike about one seventh the length of the stem, with 1-3 male and 2-3 female spikelets. Male glumes obtuse at the tip and with very pale margins; female glumes obtuse to subacute at the tip and with pale margins. Flowers with two stigmas. Utricles 2.5-4mm long, broadly oval-elliptic, flattened, with beak to 0.3mm long and truncate at the tip.
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Common Sedge Carex nigra
Native. Widespread in washlands and wet areas along rivers and streams. Flowers May to July, fruits June to August. Plants not forming tussocks, though stems can often be loosely tufted, to 10-70cm in height. Leaves 1-5mm wide, rolling inwards when drying. Flower spike one sixth to one quarter the length of the stem, with 1-2 male and 1-4 female spikelets. Male glumes usually purplish with a pale midrib, obtuse or subacute at the tip; female glumes usually black, obtuse to acute at tip. Flowers with two stigmas. Utricles 2.5-3.5mm long, broadly oval-elliptic, faintly ribbed, with beak to 0.2mm long and truncate at the tip.
A variable species, often smaller than the other species in this group and with the lowest flower bract no longer than the flower spike, utricles distinctly ribbed and stomata mostly on the upper side of the leaf.
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Silver-spiked Sedge Carex buchananii
Introduced from New Zealand as a garden ornamental and occasionally recorded as a garden escape on marginal land. Forms tight tussocks of coppery-brown foliage.
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