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.
Polygonum Roberti, Lois. = P. Raii, Bab. - The habitat of this plant is sandy seashores. The habit is prostrate. The stem is long, straggling. The leaves are flat, elliptic to lance-shaped, bending towards the stem. The ocreae, or tubular membranous stipules which surround the stem, are lance-shaped, acute, with a few distant, simple veins, and are at length torn. The anther-stalks are broader at the base. The nut is smooth, shining, and longer than the perianth. The plant is 1-3 ft. long, flowering between July and September, and is a herbaceous annual.
The habitat of this plant is shingle, seashores, sands of the coast. The habit is prostrate. The stem is woody below, stout, rigid, darker when dry, broader at the base, often buried. The leaves are elliptic to lance-shaped, the nerves netted below, thick, bluish - green below, leathery, the edges rolled back, convex above, spreading from the stem. The ocreae are lance - shaped, with branched veins at length torn, silvery-white, conspicuous, membranous, large. The anther-stalks are broader below. The fruit is longer than the perianth. The nut is smooth, shining. The plant is 3-9 in. long, flowering in August and September, and is a herbaceous perennial.
The habitat of this plant is sea-coasts. The habit is erect. The radical leaves are oblong, not so broad as in R. couglomeratus, strap-shaped, rounded, narrowed at both ends. The bracts are few, narrow. The panicle is tapering, with close whorls, all, but the 2-3 lowest, leafless. The enlarged fruiting segments are large, with nearly parallel sides, very large tubercles, and narrow, egg-shaped to oblong, blunt. The nut is egg-shaped, acute. The plant is 1-3 ft. high, flowering between June and September, and is a herbaceous perennial.
The habitat of this plant is roadsides, field borders, waste ground, and it is native on seashores, glades in woods, natural broken ground. The habit is erect, more or less of the rosette or pyramidal type. The stem is branched, sometimes reddish. The leaves are oblong, lance-shaped, acute, wavy, crisped, the base blunt, rounded, or acute. The flowers are in a panicle, with erect branches, leafy below, in crowded whorls, leafless. The flower-stalks are jointed below, twice as long as the fruiting perianth-segments, or shorter. The perianth-segments are oblong, ovate, heart-shaped, blunt, more or less entire, the upper ones having a broad, smooth tubercle. They are green or red, netted, the inner are entire or scalloped, the upper one principally tubereled. The nut is elliptic, brown. The plant is 2-4 ft. high, flowering from June to August, and is a herbaceous perennial.