Blackseed Sandspurry

Plants annual, delicate, 6-15 cm, glabrous or stipitate-glandular distally. Taproots filiform. Stems erect to ascending or arcuate-spreading, simple or branched proximally; main stem 0.3-1 mm diam. proximally. Leaves: stipules inconspicuous, dull white to tan, broadly triangular, 1-2.5 mm, apex acute to short-acuminate; blade filiform to linear, 0.5-3.5 cm, fleshy, apex blunt to apiculate; axillary leaf clusters absent. Cymes simple to 2-compound. Pedicels divergently spreading to reflexed in fruit. Flowers: sepals connate 0.2-0.5 mm proximally, lobes ± weakly 1-veined, elliptic to ovate, 1.8-2.7 mm, to 3.5 mm in fruit, margins 0.1-0.5 mm wide, apex broadly acute to rounded; petals white to rosy, ± ovate, 0.7-0.8 times as long as sepals; stamens 4-8; styles 0.4-0.8 mm. Capsules greenish, 3.3-5 mm, 1-1.3 times as long as sepals. Seeds black, often iridescent, submarginal groove usually absent, broadly ovate, compressed, 0.6-0.8 mm, shiny, sculpturing of parallel, wavy lines, not papillate (40×); wing absent or, rarely, incomplete, brownish, 0.1-0.2 mm, margins irregular.

Calif., Nev.

Flowering summer.

Alkaline places, mud flats, stream beds, sandy places; 30-1500m.

Spergularia atrosperma is a species of flowering plant in the family Caryophyllaceae known by the common name blackseed sandspurry. It is native to California and Nevada, where it grows in muddy and sandy habitat, often in moist alkaline substrates. It is a small annual herb producing a slender stem up to 15 centimeters long. It is lined with fleshy linear leaves. The inflorescence bears small flowers with five pointed sepals and five oval white or pink petals. The fruit is a capsule containing shiny, sometimes iridescent, black seeds.