PASSION FLOWER 151 and the flower, 2 to 3 in. broad, pale purple or nearly white, with a purple or sometimes flesh-colored crown, is sufficiently handsome for cultivation ; the fruit, known throughout the southern states as "maypops," is about the size of a hen's egg, dull yellow when ripe, and edible; an extract of the leaves and an infusion of the root have been used medicinal- ly, particularly as a vermifuge. This species, especially if the roots are covered with litter during winter, is sometimes hardy in northern gardens, and is a fine vine for a low trellis, though its running under ground makes it troublesome, as the shoots in spring will often appear a yard or two away from the place where the plant stood the season before. The yellow passion flower (P. lutea), growing as far north as Pennsylvania and Illinois, is a smaller plant, and its greenish yellow flowers, Blue Passion Flower (Passiflora caerulea). scarcely an inch across, are more interesting than beautiful. Our other three species, na- tives of Florida, are not showy or of any known use. P. suberosa has greenish yellow flowers and small purple fruit; P. angustifolia has yellowish flowers half an inch across, and fruit the size of a pea ; and P. Warei is equally in- significant in appearance. The commonest ex- otic species is the blue passion flower (P. cce- rulea) from South America, which has been in cultivation for nearly two centuries ; it is hardy in parts of England and on the European con- tinent, but not in our northern states; it is cultivated in cool greenhouses, and treated as a bedding plant ; if planted out in warm weather, it grows very rapidly and produces a profusion of its handsome flowers, which are very pale blue, with a purple centre and a blue crown, which has a white band in the middle. Something over 100 named passion flowers are in cultivation, including hybrids and varieties from seed; of these only a few of the more common and striking can be noticed. The edible passion flower (P, edulis), called with several others granadilla, is a very old green- house plant, and, where climbers are desired, useful for its rapid growth, dark green abun- dant foliage, and numerous white and blue, sweet-scented flowers ; its purple fruit, the size of a goose egg, is esteemed for dessert. (See GEANADILLA.) The winged (P. alata) and the four-angled (P. quadrangularis) passion flowet-s both have four-sided branches, the an- gles of which are winged ; both are free-flow- ering stove climbers, with large, sweet-scented, red or crimson flowers, in which the crown is variously colored ; the two species differ in the structure of the crown, and the last named, called the large granadilla, has an edible fruit 6 or 8 in. in diameter ; a variety, P. Decaisneana, with larger and more showy flowers than either, is supposed to be a hybrid between these two. The large-fruited passion flower (P. macro- carpa) has fruited in England, producing enor- mous berries weighing as much as 10 Ibs. each. Among the other choice species and varieties in cultivation are P. princeps, Buonapartea, Icermesina, coccinea, sanguinolenta, and circin- nata, the last named remarkable for the very long and slender wavy rays to the crown. Among those cultivated for their beauty of foliage is P. trifasciata, in which the dark olive-green leaves have three broad bands of greenish white corresponding to their three lobes, but the flowers are small and not showy. A few species are annuals; among them P. gracilis, remarkable for the rapidity of the movements of its tendrils, is one of the species observed by Darwin in studying the move- ments of climbing plants ; the intern ode car- rying the upper tendril made six revolutions at an average of 1 h. 1 m. ; a single touch near the tip of a tendril when in its most sensitive condition caused it to curve, and in two min- utes it formed an open helix. The genus tac- sonia (from tacso, the Peruvian name for the plants) differs from passiflora chiefly in having a long calyx tube, often over 3 in. long ; their habit of growth is similar, and their flowers often exceedingly brilliant; their horticultu- ral uses are identical with those of the passion flowers. In cultivation at least, some passion flowers are singularly self-sterile; though an abundance of active pollen is produced, this will not fertilize the pistils on the same plant, but it will those on a different species, and the pistils which refuse to accept their own pol- len readily become impregnated by that from another species. P. racemosa, ccerulea, and alata, in the botanic garden at Edinburgh, refused for many years to bear fruit, though the flowers of each frequently had their own pollen applied to them artificially ; but when these three were crossed in various ways with the pollen of either of the others, fruit was
