LYTHRACEAE

LOOSESTRIFE FAMILY

Elizabeth McClintock

Annual, perennial herb, shrubs, trees
Stem angled or cylindric
Leaves simple, entire, generally opposite, sometimes alternate or whorled
Inflorescence: raceme, spike, or panicle, terminal, or axillary clusters with 1–several flowers
Flower bisexual, generally radial; hypanthium cylindric to bell-shaped, generally membranous, persistent in fruit; sepals 4–6, generally persistent, appendages 3–5 or 0, alternate sepals; petals, stamens inserted on inner hypanthium; petals 4–6 or 0, alternate sepals, deciduous; stamens generally = or 2 X petals, included or exserted; ovary superior, chambers 2–6, style generally slender, stigma head-like
Fruit: capsule, opening by valves from top, splitting sometimes irregular or 0
Seeds 3–many
Genera in family: ± 25 genera, 450 species: temp, tropical, generally in wet habitats. Some ornamental or cultivated for medicine, dyes
Reference: [Graham 1964 J Arnold Arbor 45:235–250]

ROTALA

Annual, perennial herb, glabrous
Stem ascending to erect, angled
Leaves opposite, 4-ranked (rarely whorled)
Inflorescence: spike; flower 1 per axil, subtended by leaf-like bract
Flower radial; hypanthium bell-shaped; sepals generally 4, appendages 4 or 0; petals 4, tiny, < sepals; stamens generally 4, ± included
Fruit oblong to ± spheric, dehiscent by 2–4 valves
Seeds many, < 1 mm
Species in genus: ± 45 species: temp, tropical
Etymology: (Latin: wheel-like)
Reference: [Cook 1979 Boissiera 29:7–156]

Introduced

R. indica (Willd.) Koehne

Stem decumbent to erect, generally branched, 1–3 dm
Leaf 0.5–2 cm, oblong to obovate; margins thick
Inflorescence: flower 1 per axil or in short, axillary spikes
Flower: hypanthium < 2 mm; sepals deltate; appendages 0; petals pink
Fruit oblong, generally 2-valved
Ecology: Marshes, ponds
Elevation: < 100 m.
Bioregional distribution: Sacramento Valley (Butte Co.)
Distribution outside California: rice-field weed in Europe; native to se Asia