1911 Encyclopædia Britannica/Passionflower

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34595601911 Encyclopædia Britannica, Volume 20 — Passionflower

PASSIONFLOWER (Passiflora), the typical genus of the order to which it gives its name. The name passionflower—flos passionis—arose from the supposed resemblance of the corona to the crown of thorns, and of the other parts of the flower to the nails, or wounds, while the five sepals and five petals were taken to symbolize the ten apostles—Peter, who denied, and Judas, who betrayed, being left out of the reckoning.


Fig. 1.—Passiflora Coerulea, showing Leaf with Stipules, Tendril,
and detached Flower.

The species are mostly natives of western tropical South America; others are found in various tropical and sub-tropical districts of both hemispheres. The tacsonias, by some considered to form part of this genus, inhabit the Andes at considerable elevations. They are mostly climbing plants (fig. 1) having a woody stock and herbaceous or woody branches, from the sides of which tendrils are produced which enable the branches to support themselves at little expenditure of tissue. Some few form trees of considerable stature destitute of tendrils, and with broad magnolia-like leaves in place of the more or less palmately-lobed leaves which are most generally met with in the order. The leaf is usually provided at the base of the leaf-stalk with stipules, which are inconspicuous, or large and leafy; and the stalk is also furnished with one or more glandular excrescences, as in some cases are the leaf itself and the bracts. The inflorescence is of a cymose character, the terminal branch being represented by the tendril, the side branches by flower-stalks, or the inflorescence may be reduced to a single stalk. The bracts on the flower-stalk are either small and scattered or large and leafy, and then placed near the flower, forming a sort of outer calyx or epicalyx. The flower itself (seen in section in fig. 2) consists of a receptacle varying in form from that of a shallow saucer to that of a long cylindrical or trumpet-shaped tube, thin or fleshy in consistence, and giving off from its upper border the five sepals, the five petals (rarely these latter are absent), and the threads or membranous processes constituting the “corona.” This coronet forms the most conspicuous and beautiful part of the flower of many species, and consists of outgrowths from the tube formed subsequently to the other parts, and having little morphological significance, but being physiologically useful in favouring the cross-fertilization of the flower by means of insects. Other outgrowths of similar character, but less conspicuous, occur lower down the tube, and their variations afford useful means of discriminating between the species. From the base of the inner part of the tube of the flower, but quite free from it, uprises a cylindrical stalk surrounded below by a small cup-like outgrowth, and bearing above the middle a ring of five flat filaments each attached by a thread-like point to an anther. Above the ring of stamens is the ovary itself, upraised on a prolongation of the same stalk which bears the filaments, or sessile.


Fig. 2.—Flower of Passionflower cut through the centre to show
the arrangement of its constituent parts.

The stalk supporting the stamens and ovary is called the “gynophore” or the “gynandrophore,” and is a characteristic of the order. The ovary of passionflowers is one-celled with three parietal placentas, and bears at the top three styles, each capped by a large button-like stigma. The ovary ripens into a berry-like, very rarely capsular, fruit with the three groups of seeds arranged in lines along the walls, but imbedded in a pulpy arillus derived from the stalk of the seed. This succulent berry is in some cases highly perfumed, and affords a delicate fruit for the dessert-table, as in the case of the “granadilla” (P. quadrangularis), P. edulis, P. macrocarpa, and various species of Tacsonia known as “curubas” in Spanish South America; P. laurifolia is the water-lemon, and P. maliformis the sweet calabash of the West Indies. The fruits do not usually exceed in size the dimensions of a hen’s or of a swan’s egg, but that of P. macrocarpa is a gourd-like oblong fruit attaining a weight of 7 to 8 ℔.

The tacsonias, which in cultivation are generally regarded as distinct, differ from Passiflora in having a long cylindrical calyx-tube, bearing two crowns, one at the throat, the other near the base; they are stove or greenhouse plants; T. pinnatistipula, with pale rose-coloured flowers, a native of Chile and Peru, has long been in cultivation; T. Van-Volxemii, with handsome scarlet flowers, is one of the finest species.