Passiflora incarnata L.

Passionflower, May Pops

© SRTurner

Family - Passifloraceae

Habit - Perennial forb.

Stems - Vinning, with tendrils, to 10 m, glabrous to minutely pubescent.

	Stem and tendril.
© SRTurner

Leaves - Alternate, petiolate. Petioles to 3-8 cm long, finely hairy, with two prominent glands near the base of leaf blade. Leaf blades deeply 3-lobed, 6-15 cm long along the midvein, about as long as wide, the lobes usually tapered to a sharp point at the tip, the margins finely glandular-toothed, the upper surface glabrous, dark green, the undersurface sparsely and minutely hairy, lighter green, often also somewhat glaucous. Stipules 2-3 mm long, linear to narrowly lanceolate, withering and sometimes shed as the leaves develop.

	Leaves.
© SRTurner

	Leaf abaxial.
© SRTurner

	Petiolar glands.
© SRTurner

	Pressed leaves.
© DETenaglia

Inflorescence - Solitary or paired axial flowers. Flower stalks 4-10 cm long, relatively stout, elongating somewhat at fruiting. Flowers subtended by 2-4 leaflike bracts, these 4-6 mm long, elliptic to oblanceolate, the margins with minute glandular teeth and a pair of larger glands toward the base.

	Inflorescence.
© SRTurner

Flowers - 4-9 cm wide. Sepals 5, 25-30 mm long, 6-8 mm wide, narrowly oblong-elliptic, green on the outside, whitish lavender on the inside, each with the midrib having a prominent spur to 5 mm long toward the tip. Petals 5, attached to the rim of the hypanthium and alternating with the sepals, 22-25 mm long, 5-6 mm wide, narrowly oblong-elliptic, white or more commonly pale lavender to lavender. Corona filaments in several series, the outer 2 series similar, 20-30 mm long, filamentous, situated between corolla and petals, pink or lavender to purple with white to whitish yellow crossbands toward the base, the innermost series about 2 mm long, white to whitish yellow with purple tips. Stamens and pistil attached to the tip of a noticeable central stalk (known as the androgynophore, an extension of the receptacle). Stamens 5, inserted at base of ovary, the anthers attached toward the midpoint, pendent. Pistil 1 per flower, composed of 3 fused carpels, with 1 locule and numerous ovules, the placentation parietal. Styles 3, elongate, spreading to somewhat pendant, the stigmas capitate. Ovary densely velvety-hairy.

	Flower bud.
© SRTurner

	Opening bud.
© DETenaglia

	Sepals (green) and petals (white).
© SRTurner

	Flower.
© SRTurner

	Sepal spurs.
© SRTurner

	Flower.
© SRTurner

© SRTurner

	Nectaring insect becoming coated with pollen.
© SRTurner

Fruit - Berries 3-6 cm long, globose to oblong-ellipsoid, greenish yellow to yellowish orange when ripe. Seeds numerous, 4-6 mm long, 3-4 mm wide, obovate in outline, broadly rounded to more or less truncate at the tip, the surface coarsely pitted, white to light brown.

	Fruits.
© SRTurner

	Fruit interior.
© SRTurner

	Seeds.
© KBildner

Flowering - June - September.

Habitat - Streambanks, bottomland forest margins, moist depressions of upland prairies, fields, fencerows, railroads, roadsides, open disturbed areas. Often in sandy soil. Sometimes cultivated.

Origin - Native to the U.S.

Lookalikes - None.

Other info. - This species with fascinating flowers is found in a number of somewhat scattered counties, mostly south of the Missouri River. In fact, Missouri lies along the northern extent of the plant's natural range in the southeastern quadrant of the continental U.S., and there is some question whether populations north of the Missouri River represent native or introduced occurrences. When in flower, this plant cannot be mistaken for anything else in the state; there is nothing that appears even remotely similar.

The flowers are attractive and complex in structure, and seem designed to promote a particular insect-mediated pollination mechanism. A visiting insect seeking the nectary at the base of the androgynophore (the stalk bearing the functional parts of the flower) rubs against the base of one or more anthers, coating its back with pollen (see image above). The styles subsequently curve downward. Further movement of the insect, on the same or a different flower, causes the insect's back to contact the downward-oriented stigmas, delivering the pollen to its functional destination.

The plants have been used by native peoples for a variety of food, beverage, and medicinal purposes. The fruits are spongy or even hollow inside, and can be made to "pop" when stepped on, leading to one of the common names. The "passion flower" moniker refers to the Christian crucifixion event, also known as the Passion of Christ. The petals and sepals are representative of the ten faithful disciples of Jesus. The stamens, numbering 5, represent the wounds of Jesus. The three stigmas represent Trinity or the nails used in the crucifixion. The corona represents the crown of thorns. The "passion fruits" which are often consumed today are from a related species, Passiflora edulis. In this particular species the mucilage surrounding the seeds is sweet and delicious.

Photographs taken in Daytona Beach, FL., 7-2-02, and off Lee Rd. 27, Auburn, AL., 7-26-05 (DETenaglia); also at Shaw Nature Reserve, Franklin County, MO, 7-30-2006 and 7-13-2007, along the Katy Trail near the Boone Bridge, St. Charles County, MO, 8-8-2014, and near Pacific Palisades Conservation Area, MO, 7-21-2015 (SRTurner); also in St. Louis, St. Louis County, MO, 9-11-2022 (KBildner).