Sandworts & Allies
What are they?
Members of the campion family (Caryophyllaceae), these plants are related to the chickweeds but differ in their entire, not notched or deeply cut, petals. Many are rather small plants with fine leaves and may easily be overlooked.
Where are they found?
The majority of species may be found in dry, usually sandy soils - especially where wind-blown or mechanically disturbed - or in areas of short grass. One is a shade-loving species and one is coastal and such habitat choices can be useful for identification.
Identification
Habitat offers a good starting point, followed by leaf shape. Some species-pairs can be very difficult to tell apart and, for some, it may be necessary to take critical measurements of petals and sepals and to study details of the seed capsules.
Three-nerved Sandwort Moehringia trinervia
Native. Common and widespread in woodland and shady places. Flowers May to June, petals much shorter than the pointed sepals. Told from other sandworts by the relatively large, chickweed-like leaves, each with three, well-marked veins. Differs from the chickweeds in its entire, uncut petals.
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Fine-leaved Sandwort Sabulina tenuifolia
Native. Generally rare and local, with the main population occurring in Breckland on lightly disturbed, sandy soil. Flowers May to June. A small, delicate and easily overlooked plant but the combination of white flowers with long, pointed sepals and linear leaves is distinctive in our area.
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Thyme-leaved Sandwort Arenaria serpyllifolia
Native. Common and widespread on light, sandy soils or as a weed of walls, paving and similar dry habitats. Flowers May to August. An upright but low-growing species. Difficult to tell from Slender Sandwort and formerly both were considered forms of a single species. Thyme-leaved Sandwort has petals 1.6-2.7mm long, sepals 3-4mm x 1.1-1.8mm and seed capsule flask-shaped with a narrow neck.
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Slender Sandwort Arenaria leptoclados
Native. Widespread on light, sandy soils but more local than the previous species. Flowers May to August. An upright but low-growing species. Difficult to tell from Thyme-leaved Sandwort and formerly both were considered forms of a single species. Slender Sandwort has petals 1.1-1.6mm long, sepals 2.1-3.1mm x 0.5-0.8mm and seed capsule conical with straight sides.
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Mossy Sandwort Arenaria balearica
Introduced as a garden plant from western Mediterranean islands. Grown as a rockery plant and recorded from Norfolk and Suffolk as an escpae from cultivation. Flowers May to August. A creeping species with stems that root at the nodes to create spreading mats of vegetation. Flowers carried on long stalks, well above the leaves.
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Upright Chickweed Moenchia erecta
A native of dry soils in short-cropped turf that was perhaps never common but has disappeared from a number of former sites and is now rare and perhaps confined to less than 10 sites in the region. Flowers April to June. A tiny, more or less hairless and slightly bluish species, easily told from similar species by the broad white edges to the sepals.
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Jagged Chickweed Holosteum umbellatum
Perhaps once native but more likely introduced, this species is now extinct in Britain, having last been recorded in the late 19th Century. However, East Anglia was once a stronghold for the species and the first British record came from the old Norwich city walls in 1765. It may again appear in the future as it is an adaptable species and is, for example, common as an urban weed in parts of New Jersey, USA, where introduced from Europe. Flowers April to June. Almost hairless but for a region of sticky-glandular hairs on the flower stalk. Readily told from similar species by the umbel of flowers on a common stalk. Each flower stalk is reflexed in bud, becoming upright when in flower, then reflexing again in fruit.
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Sea Sandwort Honckenya peploides
Native. Common on coastal sand and shingle beaches. Flowers May to August. A distinctive species with neatly geometrically-arranged, fleshy leaves, forming spreading mats.
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