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This genus is accepted, and its native range is Tropics & Subtropics.
A specimen from Kew's Herbarium


Acanthaceae (part 2), Kaj Vollesen. Flora of Tropical East Africa. 2008

Morphology General Habit
Perennial herb with short erect or ascending stems from branched rhizome; stems up to 10 cm long, hirsute to tomentose Annual (? short-lived perennial) herb; stems creeping and rooting, ascending apically, spongy and inflated basally, up to 40 cm long, crisped-pubescent Perennial herb with short creeping stems and ascending to erect inflorescences; stems to 15 cm long, uniformly pubescent with broad glossy hairs
Morphology Leaves
Leaves sharply reflexed; lamina narrowly elliptic, largest 5–8 × 1–1.5 cm, apex acute, base subhastate, whitish hirsute-strigose above, below on veins and margins and subglabrous on lamina Leaves narrowly elliptic, largest ± 5 × 0.8 cm, apex acute, on both sides pubescent with broad glossy hairs Leaves lanceolate to narrowly ovate-elliptic, largest ± 2.5 × 0.5 cm, apex rounded, base cuneate, densely strigose-pubescent with broad glossy hairs
Morphology Reproductive morphology Flowers Androecium Stamens
Only 2 stamens developed with no trace of staminodes; filaments ± 5 mm long, with long thin hairs; anthers ± 1 mm long
Morphology Reproductive morphology Seeds
Seed ± 0.5 mm long.
Morphology Reproductive morphology Inflorescences
Inflorescence racemoid, interrupted at base, denser upwards; axes densely pubescent with broad glossy hairs; floral leaves like vegetative; flowers solitary or paired at lower nodes; bracteoles to 1 cm long; pedicels to 1 mm long Inflorescence spiciform, interrupted basally and confluent towards apex, up to 20 cm long; axes with indumentum as stems or denser and with long capitate glands intermixed towards apex; cymes up to 8-flowered (fewer upwards), sessile or basal with peduncle up to 1 mm long; bracts lanceolate, up to 1.5 cm long; pedicels ± 1 mm long; bracteoles linear-lanceolate, ± 9 mm long
Morphology Reproductive morphology Flowers Androecium Stamens Filaments
Filaments minutely puberulous, 2–3 (upper) and 4–5 (lower) mm long; anthers ± 1.5 mm long
Known only from this collection. Most closely related to H. pobeguinii from which it differs in the densely hairy stem, inflorescence and calyx, smaller leaves and larger corolla. Clearly related to H. richardsiae with which it shares the perennial habit and absence of spines in the inflorescences. It differs in the much smaller flowers. From spineless forms of H. schulli it differs in the perennial habit. It differs from both in not having the two dorsal sepals fused almost to the apex and in the relatively long linear corolla tube. Known only from this collection. With a superficial resemblance to H. cataractae, but differing in a number of important characters. It has only two fertile stamens with no staminodes, no orange spots and no long stiff hairs on the lower corolla-lip. The indumentum is also considerably denser than in H. cataractae.
Morphology Reproductive morphology Flowers
Flowers in dense sessile fascicles merging into heads in the upper part of the stem, without spines; floral leaves and bracts foliaceous, gradually smaller upwards, hard and ± bony in basal part, inner lanceolate, to 1.5 cm long, hirsute-strigose
Morphology Reproductive morphology Flowers Calyx
Calyx hirsute-strigose apically and long-ciliate, 11–13 mm long; lobes all strongly ribbed, all fused for ± 8 mm at base, ventral and lateral narrowly triangular, dorsal 2–3 mm longer and oblanceolate-spathulate Calyx uniformly strigose-pubescent, 8–10 mm long of which the basal fused part ± 3 mm; ventral and lateral lobes linear, dorsal lanceolate and ± 2 mm longer than the rest Calyx puberulous with broad glossy hairs and with capitate glands, ± 11 mm long of which the fused basal part ± 1 mm; lobes linear-lanceolate, dorsal slightly longer than rest
Morphology Reproductive morphology Flowers Corolla
Corolla bright blue, “herring-bones” inconspicuous, crisped-puberulous, no capitate glands, ± 27 mm long of which linear tube ± 12 mm and expanded tube plus limb ± 15 mm; upper lip obovate, lobes 8–9 mm long, rounded; lower lip with scattered long curly hairs, broadly obovate, lobes 7–8 mm long, rounded or retuse (central); some flowers with 4 subequal stamens, others with 2 fertile stamens (dorsal) and two staminodes without anthers; filaments glabrous, ± 4 mm long; anthers ± 3.5 mm long Corolla mauve, without (?) markings, no “herring bones”, puberulous, no capitate glands, ± 15 mm long of which the linear tube ± 5 mm and expanded tube plus limb ± 10 mm; upper lip narrowly ovate, lobes rounded; lower lip obovate, with stiff tapering hairs, lobes 2–3 mm long, rounded Corolla white with pale pink lower lip, without discernible “herring-bones”, sparsely finely puberulous, ± 12 mm long of which the tube ± 8 mm long; upper lip ovate, with two short rounded lobes; lower lip broadly obovate, without orange spots and without long stiff hairs, lobes ± 2 mm long, rounded
Morphology Reproductive morphology Fruits
Capsule and seed not seen. Capsule and seed not seen Capsule 7–8 mm long, finely puberulous near apex, with 20–24 seeds per locule
Short valley bottom grassland on sandy-loamy soil; ± 1700 m Montane grassland; ± 1800 m Small swampy area in Brachystegia woodland on grey sandy soil; ± 300 m
Range: Not known elsewhere Range: Not known elsewhere Flora districts: T4 Range: Not known elsewhere Flora districts: T4 Flora districts: T6

Native to:

Afghanistan, Alabama, Andaman Is., Angola, Argentina Northeast, Argentina Northwest, Assam, Bangladesh, Belize, Benin, Bolivia, Botswana, Brazil North, Brazil Northeast, Brazil South, Brazil Southeast, Brazil West-Central, Burkina, Burundi, Cambodia, Cameroon, Caprivi Strip, Central African Repu, Chad, China South-Central, China Southeast, Colombia, Congo, Costa Rica, Cuba, Dominican Republic, East Himalaya, Ecuador, El Salvador, Equatorial Guinea, Eritrea, Ethiopia, Florida, French Guiana, Gambia, Georgia, Ghana, Guatemala, Guinea, Guinea-Bissau, Guyana, Hainan, Haiti, Honduras, India, Ivory Coast, Jamaica, Kenya, Korea, KwaZulu-Natal, Laos, Lesser Sunda Is., Liberia, Louisiana, Madagascar, Malawi, Malaya, Maldives, Mali, Maluku, Mauritania, Mexico Gulf, Mexico Southeast, Mexico Southwest, Mississippi, Mozambique, Myanmar, Namibia, Nepal, Nicaragua, Nicobar Is., Niger, Nigeria, Northern Provinces, Northern Territory, Pakistan, Panamá, Paraguay, Peru, Philippines, Puerto Rico, Queensland, Rwanda, Senegal, Sierra Leone, Sri Lanka, Sudan, Sulawesi, Suriname, Swaziland, Taiwan, Tanzania, Texas, Thailand, Togo, Trinidad-Tobago, Uganda, Uruguay, Venezuela, Vietnam, West Himalaya, Zambia, Zaïre, Zimbabwe

Introduced into:

Mexico Northeast, Society Is., South Carolina, Virginia

Hygrophila R.Br. appears in other Kew resources:

Date Reference Identified As Barcode Type Status
s.coll. [Cat. no. s.n.], Bangladesh Cardanthera K001132507

First published in Prodr. Fl. Nov. Holland.: 479 (1810)

Accepted by

  • Govaerts, R., Nic Lughadha, E., Black, N., Turner, R. & Paton, A. (2021). The World Checklist of Vascular Plants, a continuously updated resource for exploring global plant diversity. Scientific Data 8: 215.


Flora of West Tropical Africa

  • Benoist in Bull. Soc. Bot. Fr. 60: 330 (1913).
  • —F.T.A. 5: 30

Flora of Tropical East Africa
Flora of Tropical East Africa

Herbarium Catalogue Specimens
Digital Image © Board of Trustees, RBG Kew

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at and
© Copyright 2017 World Checklist of Selected Plant Families.

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at and
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families.