Synonyms: Nomaphila APNI* Synnema APNI*
Description: Erect herbs, cystoliths present.
Leaves petiolate or sessile.
Inflorescences of 2–many flowers in axillary whorls resembling leafy spikes or racemes; bracteoles shorter than calyx. Calyx fused for over half its length. Corolla tube wider above, 2-lipped. Stamens 4. Ovary with 4–20 ovules per loculus.
Capsule fusiform, hooks prominent [or minute]; seeds 8-many with long mucilaginous hairs.
Distribution and occurrence: World: c. 20–30 species, tropical & subtropical regions. Australia: 4 species (1 species native, 3 naturalised), Qld, N.S.W., N.T., W.A.
Text by J. Everett and D.M. Crayn. Key by B. Jones and K.L. Gibbons, Dec. 2020. Taxon concept:
| Key to the species | |
1 | Freshwater aquatic perennial herb, occasionally prostrate along edges of watercourses; flowers solitary, axillary | Hygrophila polysperma |
| Erect terrestrial herb in swamps or along the edges of watercourses, tolerates innundation, usually 50–200 cm high, sometimes decumbent with age; flowers 2—12 in axillary clusters | 2 |
2 | Leaves more or less sessile, leaf apex more or less obtuse; inflorescences 2–12 flowered | Hygrophila angustifolia |
| Leaves generally petiolate, petiole to 3.5 cm long, sometimes leaves sessile; leaf apex acuminate; inflorescences 3–4 flowered Back to 1 | Hygrophila costata |
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