Spergularia macrotheca (Hornem. ex Cham. & Schltdl.) Heynh.

Plants strongly perennial with branched, woody base, stout, 5-40 cm, densely stipitate-glandular in inflorescence or throughout. Taproots becoming stout, woody. Stems erect or ascending to prostrate, usually branched proximally; main stem 0.8-3 mm diam. proximally. Leaves: stipules conspicuous, dull white to tan, narrowly triangular, 4.5-11 mm, apex long-acuminate; blade linear, (0.6-)1-5.5 cm, fleshy, apex apiculate to spine-tipped; axillary leaves 1-2+ per cluster. Cymes simple to 3-compound or flowers solitary and axillary. Pedicels erect, divergent, or reflexed in fruit. Flowers: sepals connate 0.5-1.8 mm proximally, lobes often 3-veined, ovate to lanceolate, 4.5-7 mm, to 8 mm in fruit, margins 0.3-0.7 mm wide, apex blunt to rounded; petals white or pink to rosy, elliptic to obovate, 0.9-1.3 times as long as sepals in flower; stamens 9-10; styles 0.6-3 mm. Capsules tan, 4.6-10 mm, 0.8-1.4 times as long as sepals. Seeds ± red-brown, often with submarginal groove or depression, suborbiculate to pyriform, compressed, (0.6-)0.7-1.2 mm, smooth to faintly or prominently tuberculate or sculpturing of parallel, wavy lines or of low, rounded mounds, not papillate; wing absent or white to reddish brown proximally, 0.1-0.3 mm wide, margins irregular.

Arenaria macrotheca Hornemann ex Chamisso & Schlechtendal, Linnaea 1: 53. 1826

Spergularia macrotheca is a species of flowering plant in the family Caryophyllaceae known by the common name sticky sandspurry. It is native to western North America from British Columbia to Baja California, where it grows in many types of moist coastal and inland habitat, often in alkaline and saline substrates. It may be found in marshes, alkali flats, beaches, meadows, seeps, and vernal pools. It is a perennial herb producing a narrow stem up to 40 centimeters long with a woody, thickened base and taproot. They may grow erect or prostrate across the ground. It is covered in sticky glandular hairs, especially in the inflorescence. The stems are lined with fleshy linear leaves, sometimes tipped with spines. The leaves are accompanied by triangular stipules up to a centimeter long each. Flowers occur in clusters at the end of the stem as well as in leaf axils. The small flowers have five pointed sepals and five oval white to lavender-pink petals. The fruit is a capsule containing tiny reddish brown, winged seeds.

Spergularia macrotheca là loài thực vật có hoa thuộc họ Cẩm chướng. Loài này được (Hornem. ex Cham. & Schltdl.) Heynh. miêu tả khoa học đầu tiên năm 1847.