Hygrophila (plant)

The leaves are either homomorphic, all with one form, or heteromorphic, with different forms on one plant. Homomorphic leaves are always simple and entire. Plants with heteromorphic leaves generally have pinnately divided basal leaves with either filiform (feather-like) or linear segments, and undivided leaves higher on the stem. The flowers have white to purple corollas with either 5 equal lobes or 2 lips. A lipped corolla has an erect, concave upper lip with two lobes, and a lower lip with 3 lobes. The flower has four stamens. Two may be staminodal, lacking pollen. The individual filaments of the stamens are united into pairs by a membrane. There is an inconspicuous nectar disc. Each flower yields at least 6 seeds. ==Ecology and uses==

A number of Hygrophila species and cultivars are popular within the aquascaping and aquarium hobbies, including H. angustifolia, H. corymbosa, H. lancea 'Araguaia', H. pinnatifida, H. difformis 'Water Wisteria', H. odora, H. polysperma 'Indian swampweed' and H. siamensis. Additionally, there are some striking newer forms on the market, such as the vivid hybrids of Hygrophila polysperma, 'Sunset' and 'Rosanervig'. Many members of the genus are troublesome weeds if they become established within irrigation systems, drains or drainage ditches, as well as in rice fields. Several have become established outside of their native ranges, either due to accidentally-discarded cuttings or deliberate release, such as H. polysperma in the southern United States. ==Species==

77 species are accepted: • Hygrophila abyssinica • Hygrophila acinos • Hygrophila acutangula • Hygrophila africana • Hygrophila albobracteata • Hygrophila angustifolia • Hygrophila anisocalyx • Hygrophila anomala • Hygrophila asteracanthoides • Hygrophila auriculata • Hygrophila balsamica • Hygrophila barbata • Hygrophila baronii • Hygrophila bengalensis • Hygrophila biplicata • Hygrophila borellii • Hygrophila brevituba • Hygrophila caerulea • Hygrophila cataractae • Hygrophila chevalieri • Hygrophila ciliata • Hygrophila ciliibractea • Hygrophila corymbosa • Hygrophila costata • Hygrophila didynama • Hygrophila difformis • Hygrophila episcopalis • Hygrophila erecta • Hygrophila glandulifera • Hygrophila gossweileri • Hygrophila gracillima • Hygrophila griffithii • Hygrophila guianensis • Hygrophila hippuroides • Hygrophila hirsuta • Hygrophila humistrata • Hygrophila incana • Hygrophila intermedia • Hygrophila laevis • Hygrophila limnophiloides • Hygrophila linearis • Hygrophila madurensis • Hygrophila mediatrix • Hygrophila meianthos • Hygrophila micrantha • Hygrophila modesta • Hygrophila mutica • Hygrophila niokoloensis • Hygrophila odora • Hygrophila okavangensis • Hygrophila origanoides • Hygrophila palmensis • Hygrophila paraibana • Hygrophila parishii • Hygrophila perrieri • Hygrophila petiolata • Hygrophila phlomoides • Hygrophila pinnatifida • Hygrophila pobeguinii • Hygrophila pogonocalyx • Hygrophila polysperma • Hygrophila pusilla • Hygrophila richardsiae • Hygrophila ringens • Hygrophila sandwithii • Hygrophila senegalensis • Hygrophila serpyllum • Hygrophila spiciformis • Hygrophila stocksii • Hygrophila subsessilis • Hygrophila surinamensis • Hygrophila thwaitesii • Hygrophila thymus • Hygrophila tyttha • Hygrophila uliginosa • Hygrophila urquiolae • Hygrophila velata ==Gallery==

File:Hygrophila serpyllum in Hyderabad, AP W IMG 4437.jpg|Hygrophila serpyllum File:Hygrophila difformis.jpg|Hygrophila difformis File:Hygrophila schulli Acanthaceae.jpg|Hygrophila schulli File:Hygrophila pogonocalyx.jpg|Hygrophila pogonocalyx ==References==