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).

BOERHAVIA

SPIDERLING

Annual, perennial herb
Stem prostrate to erect; internode often with sticky area
Leaf petioled; blade 1–6 cm, paler beneath, often brown-dotted
Inflorescence openly branched; unit a raceme, umbel, or head; bracts 1–3, free, not forming an involucre
Flower: perianth < 30 mm, bell-shaped, closing by afternoon; stamens 1–5; stigma ± spheric, generally exserted
Fruit < 3.5 mm, club-shaped; ridges 4–5; wings 0
Species in genus: ± 30 species: warm regions. B. spicata Choisy (fruit ribs narrow, acute) is widespread in sw US, expected as agricultural weed near Mex border
Etymology: (H. Boerhaave, Dutch botanist, 1668–1738)

Native

B. coulteri (Hook.) S. Watson

Annual
Stem decumbent to erect, < 8 dm, puberulent
Leaf: blade lanceolate to ovate-triangular, ± acute
Flower < 1.5 mm; perianth white to pale pink
Fruit 2.5 mm, glabrous; narrow (nearly closed) and wrinkled between wide ribs; tip rounded
Ecology: Gravelly hillsides, washes
Elevation: < 1150 m.
Bioregional distribution: Desert Mountains (Clark Mtns), Sonoran Desert
Distribution outside California: to Arizona, Mexico
Flowering time: Sep–Nov
B. spicata Choisy (fruit ribs narrow, acute) is widespread in sw US, expected as agricultural weed near Mex border.