Bladderwort is a native of the Northern Hemisphere, including most of North America
and parts of temperate eastern Asia. Except for occasional racemes of yellow flowers,
bladderwort remains submersed in
lakes, ponds, wet marshes, and rivers and streams up to about 6' (1.8 m) deep.
An underwater rootlike structure contains numerous “bladders”—small pouches that help keep the plant near the surface
during flowering, then sink it during dormancy periods. But the bladders have another purpose.
Common bladderwort is actually
carniverous, and the bladders are spring-loaded traps that suck in water and small organisms,
and digest them with enzymes and bacteria. They snap shut in about ⅟460th of a second!
Plants: Plants are not anchored and float freely, close to the surface.
Rootlike structures are leaves. Underwater stems sometimes produce turions—overwintering,
vegetative buds—up to about 1" (2.5 cm) around. (In many of the photos, the water surface is covered
with numerous green dots. These are duckweed, not bladderwort.)
Leaves: Leaves are alternate, ¾-2" (1.9-5 cm) long,
on a zig-zagged stalk with one or two main divisions from the base, these in turn forked into threadlike sections.
They look more like a cloud of algae than a system of
leaves. Bladders start out greenish and transparent, becoming dark red or brown to black. They are
more than ¹/₁₆" (2 mm) in size.
Flowers: A stalk up to about 10" (25 cm) in height
contains a raceme of 6-20 yellow
flowers, each resembling snapdragons and about ½-¾" (1.3-1.9 cm) in size. They appear from late May to September.
Fruits: Round capsules less than ¼" (6.3 mm) around.