There are only a few kinds of Chylisma; the flowers in terminal clusters; the calyx with a more or less funnel-form tube and four lobes; the petals four, not notched; the stamens eight, unequal; the stigma with a round top, the capsule long, membranous, with a stalk.
Chylisma
Chylísma scapoìdea var. clavaefórmis (Oenothera)
White
Spring
Ariz., Utah
A charming desert plant, from a few inches to a foot tall, with one or more, pinkish, smooth, rather leafy stems, springing from a pretty clump of smooth, bluish-green leaves. The delicate flowers are about three-quarters of an inch across and form a graceful cluster of several or many blossoms. The petals are white or yellow, often tinted with pink, with some specks of maroon at the base, and the sepals are pinkish-yellow; the stamens pale yellow; the stigma green; the pods erect.
There are several kinds of Pachylophus; perennials, stemless or nearly so; leaves from the root; calyx downy, with a long tube; petals white or pink; stamens eight, with threadlike filaments, the alternate ones longer; style threadlike; stigma four-cleft; capsule woody.
White Evening Primrose
Pachýlophus marginàtus (Oenothera)
White
Summer
Ariz., Utah, Nev., Col.
This has a few large flowers, three inches or more across, with pure-white diaphanous petals, fading to pink, and pink calyx-lobes. The buds are erect, hairy and pink, and the flowers spring from a cluster of long, downy root-leaves, narrowing to slender leaf-stalks, with hairs on the veins and on the toothed and jagged margins, and have almost no flower-stalk, but the hairy calyx-tube is so long, sometimes as much as seven inches, that it looks like a stalk. The root is thick and woody and the capsule is egg-shaped and ribbed, with no stem. There is a patch of these wonderful flowers in the Grand Canyon on Bright Angel trail, halfway between the rim and the plateau, where in a shaded spot beside a great rock the pure blossoms seem to shed a moonlight radiance. They are equally beautiful on the dry plains of Utah, where they grow in quantities.
White Evening Primrose—Pachylophus marginatus.
Chylisma scapoidea var. clavaeformis.
Sphaerostigma tortuosa.