California and south Oregon
Gravelly or sandy areas, open or lightly wooded, over a wide elevation range; 1,000 to 13,000 feet
Spatulate to oblanceolate, up to 2.3 inches long
April to September
Calyptridium monospermum generally inhabits medium to high elevation areas in California and Oregon, but is also found in lower regions, such as around San Francisco Bay. Plants can exceed one foot in height but are usually smaller; they have basal leaf rosettes and short, reddish flower stems, usually angled sideways or at an angle rather than vertically upwards. Stems also bear a few, alternate leaves, much smaller, and often withered by flowering.
Stems (two or more per rosette) are topped by a spherical inflorescence typically containing several dozen small flowers, clustered tightly together; up to 4 inches in diameter. Flowers are formed of four rounded, whitish sepals, four similarly-sized (0.3 inches) white to rose pink petals, three exserted stamens topped by reddish or dark pink anthers, and one exserted style.