(Utricularia vulgaris) Bladderwort family

Flowers - Yellow, about 1/2 in. across, 3 to 20 on short pedicels

in a raceme at the top of a stout, naked scape 3 to 14 in. high.

Calyx deeply 2-lobed; corolla 2-lipped, the upper lip erect, the

lower lip larger, its palate prominent, the lip slightly 3-lobed,

and spurred at the base; 2 stamens; 1 pistil; the stigma

2-lipped. Leaves: Very finely divided into threadlike segments,

bearing little air bladders.

Preferred Habitat - Floating free in ponds and slow streams, or

rooting in mud.

Flowering Season - June-August.

Distribution - Throughout nearly the whole of North America,

Cuba, and Mexico. Europe and Asia.

Here is an extraordinary little plant indeed, which, by its

amazing cleverness, now overruns the globe - one of the higher

order of intelligence so closely akin to the animals that the

gulf which separates such from them seems not very wide after

all. In studying the water-crowfoots (q.v.) and other aquatic

plants, we learned why submerged leaves must be so finely cut;

but what mean the little bladders tipped with bristles among the

pop-weed's threadlike foliage? Formerly these were regarded as

mere floats - a thoughtless theory, for branches without bladders

might have been observed floating perfectly. It is now known they

are traps for capturing tiny aquatic creatures: nearly every

bladder you examine under a microscope contains either minute

crustaceans or larvae, worms, or lower organisms, some perhaps

still alive, but most of them more or less advanced toward

putrefaction - a stage hastened, it is thought, by a secretion

within the bladders; for the plant cannot digest fresh food; it

can only absorb, through certain processes within the bladder's

walls, the fluid products of decay. The little insectivorous

sundew (q.v.), on the contrary, not only digests, but afterward

absorbs, animal matter. Tiny aquatic creatures, ever seeking

shelter from larger ones ready to devour them, enter the pop-weed

bladders by bending inward the free edge of the valve, which,

being strongly elastic, snaps shut again behind them instantly.

"Abandon hope, all ye who enter here," might be written above the

entrance. No victim ever escapes from that prison. Scientists are

not agreed that the bristles draw creatures into the bladder.

Whatever touches the sensitive valves is at once drawn in. "To

show how closely the edge fits," says Charles Darwin, "I may

mention that my son found a daphnia which had inserted one of its

antennae into the slit, and it was thus held fast during a whole

day. On three or four occasions I have seen long narrow larvae,

both dead and alive, wedged between the corner of the valve and

collar, with half their bodies within the bladder and half out.

Professor Cohn of Germany tells of immersing a plant of this

bladderwort one evening in clear water swarming with tiny

crustaceans, and by the next morning most of the bladders

contained them, entrapped and swimming around in their prisons.

So much for what is going on below the surface of the water: what

above it? Several flowers on the showy spike attract numerous

insects. One alighting on the lower lip must thrust his tongue

beneath the upper one to reach the nectar in the spur, passing on

its way the irritable stigma, which receives any pollen he has

brought in. Instantly it is touched, the stigma folds up to be

out of the way of the tongue when it is withdrawn from the spur

now laden with fresh pollen. It is thus that self-fertilization

is escaped. Many vigorous seeds follow in each capsule. This

marvelous piece of mechanism is what Thoreau termed "a

dirty-conditioned flower, like a sluttish woman with a gaudy

yellow bonnet"!

Not through its seeds alone, however, has the little plant

succeeded in firmly establishing itself. In early autumn the

stems terminate in large buds which, falling off, lie dormant all

winter at the bottom of the pond. In spring they root and put

forth leaves bearing bladders, which at this stage of existence

are filled with water to help anchor the plant. As flowering

season approaches, the bladders undergo an internal change to fit

them for a change of function; they now fill with air, when the

buoyed plant rises toward the surface to send up its flowering

scape, while the bladders proceed with their nefarious practices

to nourish it more abundantly while its system is heavily taxed.

The HORNED BLADDERWORT (U. cornuta), found in sandy swamps, along

the borders of ponds, marshy lake margins, and in bogs from

Newfoundland to Florida, westward to Minnesota and Texas, bears

from one to six deliciously fragrant yellow flowers on its

leafless scape from June to August. It is "perhaps the most

fragrant flower we have," says John Burroughs. "In a warm moist

atmosphere its odor is almost too strong.... Its perfume is sweet

and spicy in an eminent degree." The low scape, rooting in the

mud, has some root-like stems and branches, sometimes with a few

entire leaves and bladders. Its benefactors, bumblebees and

butterflies, with their highly developed aesthetic taste, are

attracted from afar by this pleasing flower, whose acute, curved

spur filled with nectar may not be drained by small fry, to whom

the hairy throat is an additional discouragement.


GREAT OR SPIKED WILLOWHERB FIREWEED GREATER CELANDINE SWALLOWWORT facebooktwittergoogle_plusredditpinterestlinkedinmail