(Drosera rotundifolia) Sundew family
FlowersSmall, white, growing in a 1-sided, curved raceme of buds chiefly. Calyx usually 5-parted ; usually 5 petals, and as many stamens as petals ; usually 3 styles, but 2-cleft, thus appearing to be twice as many. Scape : 4 to 10 in. high. Leaves : Growing in an open rosette on the ground ; round or broader, clothed with reddish bristly hairs tipped with purple glands, and narrowed into long, flat, hairy petioles ; young leaves curled like fern fronds.
Preferred HabitatBogs, sandy and sunny marshes.
DistributionLabrador to the Gulf of Mexico and westward. From Alaska to California. Europe and Asia.
Here is a bloodthirsty little miscreant that lives by reversing the natural order of higher forms of life preying upon lower ones, an anomaly in that the vegetable actually eats the animal ! The dogbane, as we have seen (p. 134), simply catches the flies that dare trespass upon the butterflies’ preserves, for excellent reasons of its own ; the Silenes and phloxes, among others, spread their calices, with a sticky gum that acts as limed twigs do to birds, in order to guard the nectar secreted for flying benefactors from pilfering ants ; the honey bee being an imported, not a native, in-sect, and therefore not perfectly adapted to the milkweed, occasionally gets entrapped by it ; the big bumblebee is sometimes fatally imprisoned in the moccasin flower’s gorgeous tombthe punishment of insects that do not benefit the flowers is infinite in its variety. But the local Venus’s flytrap (Dionaea muscipula), gathered only from the low savannas in North Carolina to entertain the owners of hothouses as it promptly closes the crushing trap at the end of its sensitive leaves over a hapless fly, and the common sundew that tinges the peat-bogs of three continents with its little reddish leaves, belong to a distinct class of carnivorous plants which actually masticate their animal food, depending upon it for nourishment as men do upon cattle slaughtered in an abattoir. Darwin’s luminous account of these two species alone, which occupies over three hundred absorbingly interesting pages of his ” Insectivorous Plants,” should be read by everyone interested in these freaks of nature.
When we go to some sunny cranberry bog to look for these sundews, nothing could be more innocent looking than the tiny plant, its nodding raceme of buds, usually with only a solitary little blossom (that opens only in the sunshine) at the top of the curve, its leaves glistening with what looks like dew, though the midsummer sun may be high in the heavens. A little fly or gnat, attracted by the bright jewels, alights on a leaf only to find that the clear drops, more sticky than honey, instantly glue his feet, that the pretty reddish hairs about him act like tentacles, reaching inward, to imprison him within their slowly closing embrace. Here is one of the horrors of the Inquisition operating in this land of liberty before our very eyes ! Excited by the struggles of the victim, the sensitive hairs close only the faster, working on the same principle that a vine’s tendrils do when they come in con-tact with a trellis. More of the sticky fluid pours upon the hap-less fly, plastering over his legs and wings and the pores on his body through which he draws his breath. Slowly, surely, the leaf rolls inward, making a temporary stomach ; the cruel hairs bind, the glue suffocates and holds him fast. Death alone releases him. And now the leaf’s orgie begins : moistening the fly with a fresh peptic fluid, which helps in the assimilation, the plant proceeds to digest its food. Curiously enough, chemical analysis proves that this sundew secretes a complex fluid corresponding almost exactly to the gastric juice in the stomach of animals.
Darwin, who fed these leaves with various articles, found that they could dissolve matter out of pollen, seeds, grass, etc. ; yet without a human caterer, how could a leaf turn vegetarian? When a bit of any undesirable substance, such as chalk or wood, was placed on the hairs and excited them, they might embrace it temporarily ; but as soon as the mistake was discovered, it would be dropped ! He also poisoned the plants by administering acids, and gave them fatal attacks of indigestion by overfeeding them with bits of raw beef I
Other common sundews, the Spatulate-leaved species (D. intermedia) and the Thread-leaved Sundew (D. filiformis), whose purplish-pink flowers are reared above wet sand along the coast, possess contrivances similar to the round-leaved plant’s to pursue their gruesome business. Why should these vegetables turn carnivorous ? Doubtless because the soil in which they grow can supply little or no nitrogen. Very small roots testify to the small use they serve. The water sucked up through them from the bog aids in the manufacture of the fluid so freely exuded by the bristly glands, but nitrogen must be obtained by other means, even at the sacrifice of insect victims.