Aquatic and Wetland Vascular Plants of the Northern Great Plains
Hydrocharitaceae - The Frog's-bit Family
Submersed, dioecious, perennial herbs (those included here) of calm or flowing
water, densely leafy-stemmed with whorled or decussate, sessile leaves, or plants
acaulescent with long, linear, ribbonlike leaves arising in clusters from stolons
that creep over the substrate. Flowers solitary or numerous, sessile
or peduncled, extended or freely floating to the surface at anthesis, arising
from a 2-bracted or bifid (trifid) spathe, small and nonshowy, regular; sepals
3; petals (1-)3, seldom absent; male flowers with (1)2(3) or 9
stamens; female flowers with or without staminodes; stigmas 3,
often 2-lobed, ovary inferior, ovules few to several, on 3 parietal placentae
that extend nearly to the center of the ovary. Fruit ovoid or cylindric,
few- to several-seeded, rupturing tardily and irregularly, maturing underwater.