This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
1. Sand Spurrey (Spergularia rubra, Pers.). 2. Bird's-foot (Ornithopus perpusillus, L.). 3. Horseshoe Vetch (Hippocrepis comosa, L.). 4. Rue-leaved Saxifrage (Saxifraga tridactylites, L.). 5. Meadow Saxifrage (Saxifraga granulata, L.).
No plant could be more prostrate in habit than this humble species, which spreads its flexible stems over the surface in the manner of a club moss on land or some stalkless seaweeds in the water. The stems are hairy and numerous, nearly round, with linear, flat, or thread-like leaves, shorter than the joints of the stem; and the stipules are large, united at the base, silvery and torn, membranous at the margin, not falling, inserted just below the leaves, enclosing them entirely in bud, covering the base when fully developed.
Photo. A. R. Horwood - Sand Spurrey (Spergularia rubra, Pers.)
The flowers are like those of Common Spurrey, but pink or purple, the petals equalling the calyx, and the capsule is the same length, shorter than the fruit-stalk, the seeds egg-shaped, wedge-shaped, and bordered.
The plant never rises to a height of more than 2 in. It can be seen in flower from June to September. It is annual or biennial.
The flowers are like those of Spergula, but are more conspicuous, and the plant is not hidden away amongst corn, but is prostrate on rocky soils. It is in this way less driven to self-pollination than Spurrey.
The seeds of Sand Spurrey are dispersed by its own agency. The capsule is split into valves, and the seeds are scattered when ripe close to the plant; but they may be wind-scattered, the bordered margin facilitating this.
The plant is saxicolous or a rock plant, and requires a rock soil, growing on volcanic, igneous, and granite rocks which are more or less barren.
The fungus Uromyces sparsus infests it.
From the general similarity between it and Spurrey the Latin name is a diminutive of Spergula, and rubra, red, refers to the flowers.
This is one of those plants that serve to make up a floral index, flowering only at certain hours of the day.
Essential Specific Characters: 59. Spergularia rubra, Pers. - Stem branched, prostrate, leaves linear, flat, with a bristle, stipules triangular, chaffy, flowers purple, capsule not exceeding the calyx, shorter than the pedicels, seeds not winged.