Drymaria arenarioides Humb. & Bonpl. ex Schultes
lightningweed, sandwort drymary, alfombrilla
Fruit a capsule, 15–25 seeded. Seeds strongly C-shaped, with ends touching and slightly overlapping; 0.4–1.2 mm long x 0.4–0.8 mm wide x 0.3–0.6 mm thick, with a broad dorsal groove. Seeds may assume atypical shapes due to crowding. Surface dull, light brown to brown, completely covered with minute puzzle-shaped tubercles. Hilum concealed on ventral surface. Embryo peripheral; perisperm semi-translucent.
Seeds in the genus Drymaria vary considerably with respect to seed shape, color, and surface sculpturing. Sculpturing may be merely granular to very ornate, with tubercles of various shapes and outlines. Attention to these characters can aid in species determination. Seeds in the genus Silene generally have flat sides, with tubercles in regular rows that arise from variously shaped plates.
dry areas, acid soils, hills and plains, stressed rangelands
Drymaria arenarioides is a spreading perennial herb, up to 20 cm long. It invades rangeland, displacing desirable vegetation. Saponins in this plant are highly toxic to cattle, sheep and goats, resulting in major cattle losses in Mexico. While the plant is not documented in the U.S., it is spreading northward, reportedly to within one mile of New Mexico.