Common name:
Lavender-leaf sundrop
Scientific name:
Calylophus lavandulifolius
Synonym:
Oenothera lavandulifolia
Range:
Nevada, east across the Four Corners states to west Texas and the southern Great Plains
Habitat:
Dry, open places; rocky, sandy or gravelly, from 3,500 to 8,500 feet
Leaves:
Alternate, unlobed, closely-spaced, linear to narrowly lanceolate, up to 2 inches long
Calylophus lavandulifolius is a low growing plant in the evening primrose family, with small, inconspicuous stems and leaves, though is easily spotted when in bloom owing to the large yellow flowers, up to 2 inches wide, at the tip of slender tubes (the hypanthium) of up to 5 inches. Petals have slightly irregular margins, and they wither to orange then purple. The four lance-shaped sepals are pale yellow, and recurved when mature. Sepals and ovary have a covering of short, spreading hairs. Buds are greenish, striped with red. The eight yellow stamens are exserted, as is the (longer) pistil, which is toped by a four-lobed, disc-shaped stigma. Flowers are solitary, from the upper leaf nodes.
Leaves and stems also have a covering of short, greyish hairs. Unlike many other evening primrose species, calylophus lavandulifolius blooms during the day, and it often forms colonies of dozens of plants.