Elodea Michx.

Hydrocharitaceae, David Simpson. Flora of Tropical East Africa. 1989

Morphology General Habit

Dioecious, submerged, freshwater, perennial herbs

Morphology Roots

Roots simple, adventitious, without root-hairs, arising from nodes

Morphology Stem

Stems elongate, stoloniferous or erect, terete, simple or branched from axils; branches 1 per axil, subtended at the base by 2, sessile, opposite, scale-like leaves

Morphology Leaves Stipules

Stipules 0

Morphology Leaves

Nodal scales 2–4 per leaf, ovoid to orbicular with entire margins All other leaves sessile, in whorls of 2–8, linear to lanceolate or narrowly oblong, shortly acuminate to subobtuse, patent, spreading or recurved, flaccid, somewhat translucent, with 1 apical spine; margins green or hyaline, serrulate to denticulate, the teeth usually patent; venation consisting of midrib only

Morphology Reproductive morphology Flowers

Flowers unisexual Female flower: sepals 3, ovate to suborbicular, obtuse or cucullate, reflexed; petals 3, widely elliptic to orbicular, rounded, spreading; staminodes 3, linear, papillose. Ovary of 3 carpels, ovoid, 1-locular, placentation parietal; ovules up to 9, orthotropous; perianth-tube filiform, carrying perianth to just above the water-surface; styles 3; stigmas 3, irregularly 2–4-lobed, linear, papillose on adaxial surface, with 2 weakly 3-lobed nectaries at their base Male flowers long-pedicellate, remaining attached to the plant at anthesis; sepals 3, ovate to suborbicular, obtuse or cucullate, usually reflexed at anthesis; petals 3, widely elliptic to orbicular, rounded, spreading; stamens 9, in whorls of 3, anthers erect, 4-thecous, latrorsely dehiscent; filaments flattened, club-shaped or linear, nectaries 3-lobed, the lateral lobes shorter to longer than the central lobe

sex Male

Male flowers long-pedicellate, remaining attached to the plant at anthesis; sepals 3, ovate to suborbicular, obtuse or cucullate, usually reflexed at anthesis; petals 3, widely elliptic to orbicular, rounded, spreading; stamens 9, in whorls of 3, anthers erect, 4-thecous, latrorsely dehiscent; filaments flattened, club-shaped or linear, nectaries 3-lobed, the lateral lobes shorter to longer than the central lobe Male spathe solitary in leaf-axil, sessile, narrowly ovoid, 2–5-flowered

Morphology Reproductive morphology Inflorescences

Female spathes 1(–2) in leaf-axil, sessile, narrowly ovoid, 1(–2)-flowered Male spathe solitary in leaf-axil, sessile, narrowly ovoid, 2–5-flowered

sex Female

Female spathes 1(–2) in leaf-axil, sessile, narrowly ovoid, 1(–2)-flowered Female flower: sepals 3, ovate to suborbicular, obtuse or cucullate, reflexed; petals 3, widely elliptic to orbicular, rounded, spreading; staminodes 3, linear, papillose. Ovary of 3 carpels, ovoid, 1-locular, placentation parietal; ovules up to 9, orthotropous; perianth-tube filiform, carrying perianth to just above the water-surface; styles 3; stigmas 3, irregularly 2–4-lobed, linear, papillose on adaxial surface, with 2 weakly 3-lobed nectaries at their base

Morphology Reproductive morphology Fruits

Fruit ovoid, smooth

Morphology Reproductive morphology Seeds

Seeds ellipsoid, covered in elongated or spine-like cells.