Nesaea Comm. Ex. Kunth
tropical Africa, Asia, Central and South America, Australia
Species commonly cultivated
Nesaea crassicaulis (Guill. & Perr.) Koehne (Africa, Madagascar)
N. pedicellata Hiern (Tanzania, Mozambique)
Annual or perennial. Stem erect or ascending, usually four-sided (when emersed). Leaves opposite, decussate, sessile, linear to ovate; margin entire. Inflorescence sessile or pedicellate. Flowers axillary, solitary or in many-flowered head, actinomorphic; sepals 4-5; petals 4-5, pink to purple. Dispersal by seeds or stem fragments.
limestone seeps, river and creek banks, springs, margins of lakes, other marshy to damp areas
Nesaea contains over 50 species (six aquatic) with only two species commonly cultivated for aquaria. The genus is morphologically diverse in Africa. Nesaea and Ammannia are separated only with great difficulty based on presumed differences in capsule dehiscence. There is considerable variation in color from deep red to yellow shown in Nesaea spp. when grown submersed; the degree of color depends on light and nutrient levels. Nesaea pedicellata has approximately half of its stamens (4-5) longer than the calyx and half (4-5) the same length. All of the stamens are the same length as the calyx in N. crassicaulis.