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to seize their prey or to hold it more securely. Among the former are the pitfall traps, shaped like pitchers or trumpets. Of these the best-known family is the Sarraceniaceae, or pitcher plant family, with nine species confined to eastern North America, from Labrador to Florida and westward to Iowa and Kentucky, with most species in the southeast. The pitcher may stand more or less upright, bearing above its mouth an expanded projection or arching hood, sometimes miscalled a lid; it does not close the pitcher but may diminish the amount of rain that falls into it. Or it may lie recumbent on the ground, like Sarracenia psittacina, with a recurved, cowled end that directs the narrow mouth horizontally toward the base of the tube. The slender upright pitcher of S. flava is often three feet (90 cm.) high by two or three inches (5 or 7.5 cm.) wide. All these pitchers have a broad or narrow wing along the front. They tend to be brightly decorated, with white, red, purple, or yellowish spots or stripes on a generally green ground. These colors not only attract insects but, together with the large, inverted, purple or yellow flowers raised on long stalks above the rosette of

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pitchers, they have induced horticulturists to grow them in cool greenhouses, making many hybrids.

A feature common to all carnivorous plants is an abundance of glands of diverse forms and functions, some of which lure visitors with nectar or sweetish mucilage, while others secrete enzymes to digest victims or to absorb the products of their dissolution. Drawn by its colors to a pitcher of Sarracenia purpurea, the Side-saddle Flower or Huntsman's Cup, an insect finds nectar glands scattered over its outer surface among abundant hairs. If, creeping over the exterior, it reaches the pitcher's mouth, it enters an insidious pitfall in which four zones are distinguished. The first is the cordate, emarginate hood, where the hairs amid the nectar glands point strongly downward, directing the creature inward to the second zone, which is a narrow collar of velvety aspect, covered with fine, downwardly directed ridges and many more glands. Sliding still farther inward while it enjoys the nectar, the deluded insect reaches zone three, which covers half of the pitcher's interior with a smooth, glassy, gland-dotted surface that precipitates it into the fourth zone. This pit is surrounded by long, slender, downward-pointing, glassy hairs, which impede the victim's escape. Here are no more nectar glands to solace it while it drowns or otherwise succumbs. Absence of a cuticle over much of this zone facilitates absorption.

Species of Sarracenia differ in the amount of water their pitchers contain before they open or which is secreted into them after opening. The liquid in young, unopened pitchers appears always to be sterile, but that into which animals have fallen contains bacteria, as is to be expected. In Sarracenia, as in other carnivorous plants, the possibility of decomposition by bacterial action has persistently plagued the interpretation of the many experiments designed to demonstrate the presence, and to test the potency, of digestive enzymes are present in the pitcher fluid of all species of Sarracenia. In most it acts best in an alkaline medium, but in some acid is more favorable, as in the human stomach. Often it was found necessary to add an alkali (or an acid) to the pitcher fluid to obtain positive results. In any case, the several species differed greatly in the rapidity of digestion; in some it was swift but in others it

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Purple pitcher plant or huntsman's cup, Sarracenia purpurea

required many days. Water and nitrogenous compounds released by digestion or decay are absorbed by the tissues at the bottom of the pitchers. Birds occasionally drink from them.

Also in the pitcher-plant family is Darlingtonia, with a single species, calfornica, in the north of that state and in adjacent south-

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ern Oregon, where it grows in swamps and on wet soil in open woodland glades. Springing from a perennial