Wood-rushes
What are they?
The members of the genus Luzula are a surprisingly divers group of plants, related to the true rushes and placed in the family Juncaceae. As is usual in botanical taxonomy, these plants are grouped together based on details of their floral structure (and more recently, genetic similarities), but the outward appearance of their flowers spikes is very variable from one species to another. Wood-rushes can be told from superficially similar sedges and club-rushes by the distinct, white hairs on their leaf margins and bases and by the arrangement of six, bract-like tepals in the flowers. At flowering, the female stigmas emerge ahead of the male stamens, often pushing out beyond the still-closed tepals. Afterwards, the tepals open out, star-like and the anthers mature and release their pollen, so the appearance of the flowers can vary according to what stage of development they are at.
Where are they found?
Wood-rushes have less of an affinity to wetlands than is usual amongst the true rushes in the genus Juncus. Though some species favour rather damp woodland, others can be found on dry heathland or calcareous grassland and soil type can sometimes be useful in aiding species identification.
Identification
This is a rather diverse set of plants, best identified as a group by the broad, grass-like leaves that have distinctive white hairs around their leaf edges and bases, especially when first emerging. The diversity of appearance in the flower spikes offers the main difference between the species and this makes identification mostly straightforward. Field and Heath Wood-rushes are distinctly more alike and the habitat and style of growth offer the best ways to separate them.
Field Wood-rush Luzula campestris
Native. Common throughout the region in short grass habitats on both calcareous and acidic soils. Often a feature in spring of lawns and short-cropped grass in gardens, churchyards and similar places. Flowers March to June. Plants 10-30cm in height, loosely tussocky and spreading by short stolons to produce mats of vegetation. Leaves broad and grass-like with the distinctive white hairs of the group. Flowerhead dense at first but later becoming more open and often nodding as the fruits develop. Anthers more than 1.5 times as long as their filaments.
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Congested Wood-rush Luzula congesta
(Luzula multiflora subsp. congesta) Native. Widespread in a variety of habitats on acid soils and thus a little more localised than Field Wood-rush. Flowers April to June. Plants 10-60cm in height, tightly tussocky and without creeping stolons, so not forming spreading mats. Leaves broad and grass-like with the distinctive white hairs of the group. Flowerhead branched, but all branches short, producing a tight, club-shaped head, even in fruit. Anthers less than 1.5 times as long as their filaments. Lowest flower bract usually longer than inflorescence; tepals longer than fruit.
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Heath Wood-rush Luzula multiflora
Native. Uncommon, though widespread and scattered thinly across the region on less chalky soils. Differs from Congested Wood-rush in having a more open flowerhead with longer side branches, the lowest flower bract not longer than the inflorescence and tepals shorter than fruit.
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Great Wood-rush Luzula sylvatica
Native. Though common in the wetter North and West of Britain, this is a rare species in East Anglia, recorded from a scattering of ancient woodlands, mostly in Mid-Norfolk and East Suffolk. Flowers May to June. Plants 40-80cm in height, loosely tussocky and spreading by short stolons to produce clusters of leaf rosettes. Leaves broad with the distinctive white hairs of the group. Flowerhead large, many-branched and many-flowered, at first upright but eventually pendulous.
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Hairy Wood-rush Luzula pilosa
Native. Uncommon in old woodland, mostly scattered across boulder clay areas from Mid-Norfolk and North-east Suffolk to North-east Essex, but also on chalky banks in the South-west of our region. Flowers April to June. Plants 15-35cm in height, loosely tussocky and spreading by short stolons to produce clusters of very leafy rosettes. Leaves broad but, despite the name, this is the least hairy of our wood-rushes, typically with only a few basal hairs on the leaves. Flowerhead small and spindly, with single florets at the ends of thin branchelets which elongate even further and often reflex after flowering. Fruits distinctly pear-shaped.
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Southern Wood-rush Luzula forsteri
Native. As the name suggests, this is largely a southern species in Britain and, though there are old records from South-east Suffolk, this species seems to have been lost from East Anglia at present. Flowers April to June. Plants 15-35cm in height, loosely tussocky and spreading by short stolons. Leaves mostly basal and typically broad with white hairs at the margins. Flowerhead ratrher upright but spreading with flowers carried singly or occasionally in pairs on the stems. Fruits oval-rounded.
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Snow-white Wood-rush Luzula nivea
Introduced from Central Europe as a garden ornamental and first found in woodland, well away from houses, north of Norwich in 2022. Easily told from our other wood-rushes by its pure white flowers. Rather like an overgrown White Beak-sedge, but told from that species by habitat and the white hairs on the leaves, as well as the flowers with six tepals.
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