A N F Keys
1 Shoots with lower leaves opposite but canopy leaves and bracts helically alternate; hypanthium cylindric at or after anthesis; sepals, petals, and stamens 5−6 .. Lythrum
1' Shoots with leaves and bracts only opposite decussate; hypanthium bell-shaped; sepals, petals, and stamens (3−)4(−5)
2 Leaves short-petiolate; flowers 1 per axil; petals white to rose; capsule dehiscent by 4 valves .. Rotala ramosior
2' Leaves sessile and clasping; flowers (1−)3−5 per axil; petals rose-purple to strong reddish purple; capsule spheric, irregularly dehiscent .. Ammannia coccinea [pics]
1 Perennial herb with woody rhizome; flowers 7−12 mm across, heterostylous (2 flower forms); petals orchid to light purple .. Lythrum californicum [pics]
1' Annual (biennial) rooting along prostrate stems; flowers 5−7 mm across, homostylous (1 flower form); petals pink to rose .. Lythrum hyssopifolia [pics]
The text of the above keys used with permission from
A Naturalist's Flora of the Santa Monica Mountains and Simi Hills, California
© Copyright
Barry A. Prigge and Arthur C. Gibson
2013