CONVOLVULACEAE

MORNING-GLORY FAMILY

Lauramay T. Dempster (except Calystegia)

Perennial (annual), generally twining or trailing
Leaves alternate
Inflorescence: cyme or flowers solitary in axils; pedicels often with 2 bracts
Flower bisexual, radial; sepals 5, ± free, overlapping, persistent, often unequal; corolla generally showy, generally bell-shaped, ± shallowly 5-lobed, generally pleated and twisted in bud; stamens 5, epipetalous; pistil 1, ovary superior, chambers generally 2, ovules generally 2 per chamber, styles 1–2
Fruit: generally capsule
Seeds 1–4(6)
Genera in family: 50 genera, 1,000 species: warm temp to tropical; some cultivated as ornamental
Recent taxonomic note: Recently treated to include Cuscutaceae [Angiosperm Phylogeny Group 1998 Ann Missouri Bot Gard 85:531–553].
(Family description, key to genera by L.T. Dempster)

CRESSA

ALKALI WEED

Perennial, subshrub, canescent
Stem prostrate to erect, not twining
Leaf entire
Inflorescence: flowers solitary in upper axils, appearing like a 1-sided, leafy raceme
Flower: calyx ± erect, concealing corolla tube; corolla lobes ± = tube, exserted; ovary chambers 2, ovules 4, styles 2, stigmas head-like
Species in genus: 5 species: tropical & subtropical
Etymology: (Greek: a Cretan woman)

Native

C. truxillensis Kunth

ALKALI WEED

Stem 7–25 cm, much-branched from base, densely silky-canescent
Leaf generally < 1 cm, ± sessile, ± elliptic
Inflorescence: peduncle short, bracted
Flower 5–8 mm; sepals elliptic; corolla white, persistent, lobes ovate, acute; stamens and styles exserted
Seed often 1, by abortion of others
Chromosomes: 2n=28
Ecology: Saline and alkaline soils
Elevation: < 1200 m.
Bioregional distribution: California Floristic Province, Desert
Distribution outside California: to Oregon, Texas, Mexico
Flowering time: May–Oct
Synonyms: var. vallicola (A. Heller) Munz; C. cretica L. misapplied
Horticultural information: DRY, SUN, ALKALINE, SALINE: 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24; INV.