Sedge Group 7
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 three stigmas separates them from group 4 sedges. They differ from sedges in groups 5 and 6 in that the spikelets do not become clearly pendulous as the fruits develop (though the entire spike may lean to one side). Note that some species may or may not have pendulous lower spikelets, so they appear in both groups for the purposes of aiding identification.
Where are they found?
These are sedges of heathy or wetland habitats, especially species-rich fen habitats and peaty, wet heaths.
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). The yellow sedges are a difficult group and have had various names over time as opinions on their taxonomy has swung back and forth. You may find some plants that are intermediate and refuse to be identified!
Thin-spiked Wood Sedge Carex strigosa
Native. Rare in our region, being most frequent in old woods in the Colchester-Ipswich area. Flowers May to June, fruits June to September. Plants grow to 35-75cm in height, often forming distinct colonies of leafy tussocks. Leaves fairly broad, bright green, 6-10mm wide, strongly keeled and folded. Flower spike emerges upright but the female spikelets usually become pendulous as the fruits develop. Spikes have 1 male and 3-6 female spikelets. Utricles 3-4mm long, narrowly elliptical, often curving outwards from the main stem; beak short, 0.3-0.5mm in length.
Greatly resembles Common Wood Sedge in general appearance and best told by its typically broader leaves and the size and shape of the utricles.
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Green-ribbed Sedge Carex binervis
Native. Very uncommon in our region with a thin scattering of locations on heathy, acidic soils, mostly in Norfolk. Flowers June, fruits June to August. Plants grow to 15-75cm in height, often forming distinct colonies of leafy tussocks. Leaves dark green, 3-6mm wide, strongly keeled and folded. Flower spike elongated with the lower female spikes being particularly widely spaced. The spike stays more or less upright but often leans strongly to one side, with only the lowermost spikelet becoming pendulous. Spikes have 1 male and 2-4 female spikelets. Utricles 3.5-4.5mm long, broadly elliptical, ripening reddish- or purplish-brown, with two, well-marked veins or ridges; beak 1-1.5mm in length.
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Distant Sedge Carex distans
Native. A plant of wet ground rather than open waterways. Scattered thinly at a few inland sites but mostly a plant of brackish, coastal wetland habitats, dune slacks and the upper edges of saltmarsh. Flowers May-June, fruits June to July. Plants grow to 15-90cm in height, often forming distinct colonies of leafy tussocks. Leaves dull green, becoming brown, 2-6mm wide, flat. Flower spike elongated after flowering, with the lower female spikes being particularly widely spaced. Spikes have 1 male and 2-4 female spikelets. Female glumes pale to mid-brown with narrow, papery margins. Utricles 3.0-4.5mm long, broadly elliptical and roundly three-sided; ribs all similar in prominence (not with two more prominent than the others), beak 0.7-1mm in length.
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Long-bracted Sedge Carex extensa
Native. Rare in the East of England with most records from the North-west coast of Norfolk, particularly around the Wash. A plant of salt-splashed, brackish wetlands, growing on the higher parts of saltmarshes. Flowers June-July, fruits July to August. Plants grow to 40cm in height. Leaves greyish-green or slightly glaucous, becoming reddish-brown, 2-3mm wide, lightly keeled. Flower spike one third to a half the length of the stem, with very long, leaf-like bracts that greatly exceed the length of the flower spike. Spikes have 1 male and 2-4 female spikelets. Male glumes reddish-brown with a green midrib and obtuse tip; female glumes similar but with a mucronate tip. Utricles 2-4mm long, oval or elliptical and weakly ribbed; beak 0.5-1mm in length.
Readily recognised by the relatively short and compact spikelets and the surprisingly long, leaf-like bracts.
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Common Yellow Sedge Carex demissa
(Carex flava subsp. demissa, Carex oederi subsp. demissa) (Carex viridula subsp. oedocarpa) Native. Uncommon but widely scattered in peaty fens washed with chalky groundwater. Flowers June-July, fruits July to August. Plants 5-20cm in height. Leaves green to yellowish-green, 2-5mm wide, flat. Spikes have 1 male spikelet (which is clearly stalked) and 2-5 female spikelets (the lowest always remote from the others) with leaf-like bracts, the lowermost greatly exceeding the length of the flower spike. Male glumes pale brown with a green midrib and obtuse tip; female glumes similar but with a subacute tip. Utricles 3-4mm long, oval or elliptical, green and prominently veined; beak 0.8-1.3mm in length, straight, usually less than one third of the length of the utricle.
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Long-stalked Yellow Sedge Carex lepidocarpa
(Carex flava subsp. lepidocarpa, Carex viridula subsp. lepidocarpa) (Carex viridula subsp. brachyrhyncha) Native. Uncommon in peaty fens washed with chalky groundwater, mostly in the northern half of our region. Flowers June-July, fruits July to August. Plants 30-50cm in height. Leaves green to yellowish-green, 1.5-2.5mm wide, flat. Spikes have 1 male spikelet (which is clearly stalked) and 2-5 female spikelets (the lowest a little remote from the others) with leaf-like bracts, the lowermost equal to or exceeding the length of the flower spike. Male glumes pale brown with a green midrib and obtuse tip; female glumes similar but with a subacute tip. Utricles 3-5.5mm long, obovoid, green and prominently veined; beak 1.5-2mm in length, curved or bent, more than one third of the length of the utricle.
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