Avicennia

Daniel, Thomas F., 2016, Avicennia (Acanthaceae: Avicennioideae) in North America and Mesoamerica, Proceedings of the California Academy of Sciences 63 (5), pp. 163-189 : 165-167

Key to the Native and Naturalized Species of Avicennia in North America and Mesoamerica

1a. Flower actinomorphic; corolla yellowish to orangish, upper lip entire or bifid with the division to 0.2 mm long, the four corolla lobes ovate-triangular to ovate-elliptic; stamens inserted in distal half of corolla tube near base of lobes, oriented equally distant from each other and dehiscing toward the central gynoecium, 1.5– 2 mm long, filaments 0.5– 0.8 mm long; naturalized in southern California ............................. A. marina subsp. australasica

1b. Flower ± 2-labiate; corolla white to cream (often with yellow in throat), upper lip bifid to 2-parted with the division to 3 mm long, the 4–5 lobes oblong to obovate; stamens inserted at midpoint or in proximal half of corolla tube, oriented in pairs adjacent to upper lip of corolla and dehiscing toward lower lip, 2–5 mm long, filaments 1.5– 4 mm long; native in southeastern U.S.A., Mexico, and Central America........................................ 2

2a. Internodes of young stems glabrous; 1-flowered dichasia ± evenly distributed along rachis, internodes near midspike 3.5–7 (–9) mm long, rachis clearly visible; internal surface of corolla lobes glabrous; 2 stamens exserted from mouth of corolla and 2 stamens included in corolla tube (or only partly exserted from it); style not evident after corolla dehisces; capsule blackish when dry........................................................ A. bicolor

2b. Internodes of young stems usually scurfy with shiny whitish trichome- or scale-like projections to 0.05 mm long; 1-flowered dichasia congested at or toward apex of rachis (± headlike), internodes near midspike mostly 0.8– 4 mm long, rachis not or barely or only partially visible; internal surface of corolla lobes densely pubescent (at least in distal half); all 4 stamens exsert- ed from mouth of corolla; style usually conspicuous after (and often before) corolla dehisces; capsule usually grayish when dry..................................... A. germinans