hairy four o’clock

not listed

N5 - Secure

SNR - Unranked

not listed

Hairy four o’clock is an erect perennial rising from a thick, dark, fleshy or woody, taproot.

The stems are hairy, especially near the nodes. They are usually erect, but they may recline on the ground with the tips ascending.

The leaves are opposite, untoothed, hairy, either lance-shaped or lance-egg–shaped, almost stalkless, and taper to the base. They are spreading or strongly ascending at a 10° to 90° angle. The upper leaf surface is green to grayish or bluish green. The principal leaves are ⅜″ to ¾″ wide.

The inflorescence is single branched clusters at the end of each stem branch and in the leaf axils. The clusters appear at the end of ⅛″ to ½″ long hairy stalks. The clusters have 3 flowers each and are themselves hairy.

The flowers are ¼″ to ½″ wide. They have little or no fragrance. There are 5 pale pink petal-like sepals. The sepals are fused at the base forming a tube, then flare outward. There are 5 hairy bracts, ⅛″ to ¼″ long, at the base of the flower that are fused into a pale green, sometimes tinged with purple, narrowly to widely bell-shaped cup. The flowers open in the late afternoon, giving this plant its common name, remain open all night, and close in the morning.

The fruit is a one-seeded achene. It is subtended by the persistent, bell-shaped fused bracts that have increased in size as the fruit developed, becoming ⅓″ to ½″ long.

8″ to 40″

Pale pink

Heart-leaved four o’clock (Mirabilis nyctaginea) has a hairless, distinctly forked stem. The leaves are wider, often hairless, and on longer leaf stalks. The bract cups are hairless.

Narrow-leaved four o’clock (Mirabilis linearis) has linear leaves.

Dry. Prairies, hills, disturbed sites. Full sun.

May to August

Sources

2, 3, 4, 5, 7, 24, 28, 30.

Native

Plant

Inflorescence

Flower

Leaves

Infructescence

Location: Kellogg Weaver Dunes SNA, Weaver Dunes Unit