1. Frankenia Linnaeus, Sp. Pl. 1: 331. 1753; Gen. Pl. ed. 5, 154. 1754.
[For Johann Frankenius, 1590–1661, Swedish botanist] [For Johann Frankenius, 1590–1661, Swedish botanist]
Branches articulated, often swollen at nodes, usually differentiated into long and short shoots, hairs simple. Leaves petiolate or sessile, salt crystals usually present on leaf surfaces, sometimes forming solid crust, short-shoot leaves in axillary fascicles; petiole sometimes inconspicuous, narrow to broad distally, margins usually ciliate. Inflorescences: floral bracts leaflike, usually connate basally into verticels of 4, clasping calyx base (rarely adnate to calyx base). Flowers: calyx tube cylindric [campanulate], strongly rounded-ribbed; 4–6[–7]-lobed, petals white, pink, violet, or blue-purple, oblong-oblanceolate to spatulate, claw linear, broadening slightly at apex, to narrowly cuneate, limb apex truncate or rounded, erose-denticulate to sinuous, glabrous; anthers yellow or red to yellowish pink to purplish red; ovary with [1–]2–60[–100] ovules, funiculi ascending and bearing erect ovules or deflexed and bearing pendulous ovules, usually free, infrequently adnate to carpel wall for part of their lengths. Seeds ivory to golden brown, ovoid-conic or elongate-ovoid to oblong- or ovoid-ellipsoid or ellipsoid. x = 5.
Species ca. 70 (5 in the flora): United States, Mexico, South America, Eurasia, Africa, Atlantic Islands, Australia; introduced in West Indies.
Frankenia species vary in the degree of revoluteness of the leaf margins. This is most easily determined on fresh or softened material; loosely revolute margins will often tend to become somewhat more revolute on drying but can still be distinguished from tightly revolute margins that are not readily unrolled.
SELECTED REFERENCE Whalen, M. A. 1987. Systematics of Frankenia (Frankeniaceae) in North and South America. Syst. Bot. Monogr. 17: 1–93.
