NYCTAGINACEAE

FOUR O'CLOCK FAMILY

Richard Spellenberg

Perennial, shrub, tree, glabrous or hairy
Stem often forked
Leaves opposite, sessile or petioled, pairs generally unequal; blade generally entire
Inflorescence generally forked; of spikes, clusters, or umbels, each unit sometimes with a calyx-like involucre
Flower bisexual, radial; perianth of 1 whorl, petal-like, bell- to trumpet-shaped, base hardened, tightly surrounding ovary in fruit, lobes 4–5, generally notched to ± bilateral; stamens 1–many; ovary superior (appearing inferior because of hardened perianth base), style 1
Fruit: achene or nut, smooth, wrinkled, or ribbed
Genera in family: 30 genera, 300 species: warm regions, especially Am; some ornamental (Bougainvillea ; Mirabilis , four o'clock).

MIRABILIS

FOUR O'CLOCK

Perennial, subshrub
Stem repeatedly forked, decumbent to erect
Leaf generally petioled
Inflorescence forked; calyx-like involucres densely clustered or solitary in axils, bell- to saucer-shaped; flowers 1–16 per involucre, blooming sequentially
Flower: perianth funnel- to bell-shaped, lobes 5; stamens 3–5, generally exserted; stigma ± spheric, generally exserted
Fruit ± round to club-shaped, smooth to 5-ribbed; wing 0
Species in genus: ± 60 species: Am, Himalayas
Etymology: (Latin: wonderful)
Fls open in evening, close in morning. Spp. intergrade; Hermidium , Oxybaphus sometimes segregated, but intergrade with other species; careful study needed. [Pilz 1978 Madroño 25:113–132]

Native

M. tenuiloba S. Watson

LONG-LOBED FOUR O'CLOCK

Stem trailing to erect, < 5 dm, glandular-hairy
Leaf ascending; blade 2.5–5 cm, narrowly to broadly triangular, glandular-hairy
Inflorescence: involucres ± densely clustered in upper axils, narrowly bell-shaped, spreading glandular-hairy; bracts 5, 11–13 mm, < 1/2 fused, lobes narrowly lanceolate; flower 1 per involucre
Flower: perianth 12–15 mm, funnel-shaped, whitish, lightly hairy
Fruit ± 5 mm, ovoid, smooth, blackish brown, glabrous
Ecology: UNCOMMON. Rocky slopes in desert scrub
Elevation: < 500 m.
Bioregional distribution: w Sonoran Desert (Imperial, Riverside, San Diego cos.)
Distribution outside California: Baja California
Flowering time: Mar–May
Horticultural information: TRY.