Flora of North America species comparison

Passiflora incarnata probably has been expanding its range due to its preference for open, disturbed areas, possibly since prior to European settlement (K. J. Gremillion 1989). The species is probably native no farther north than southern Illinois and Ohio, central or southern Virginia, and central West Virginia (C. Frye and B. McAvoy, pers. comm.); it is very cold-hardy, and is introduced sporadically northwards (for example, G. Moore 1989; G. J. Wilder and M. R. McCombs 2002). This species can spread over large areas in well-drained soil, primarily by suckers from deep, far-spreading roots, and has been considered a weed of croplands (W. C. Muenscher 1980). Despite its aggressiveness, it is considered rare in some parts of its range (Indiana, Ohio).

Passiflora incarnata is used for its sedative properties (J. A. Beutler and A. DerMarderosian 2005; A. Chevallier 1996). The species was possibly cultivated by Native Americans, or at least exploited by them for its edible fruit, for over 3,000 years prior to European settlement in North America (K. J. Gremillion 1989). The Cherokee used it for skin infections and earaches, as a liver tonic, and for weaning babies, and the Houma used it as a blood tonic (D. E. Moerman 1986). Fruits of P. incarnata vary in palatability, more flavorful ones suggesting potential value as a fruit crop (C. M. McGuire 1999).

A similar species, Passiflora edulis Sims, has been sparingly naturalized in southern Florida (R. P. Wunderlin and B. F. Hansen 2003), although such material has not been collected there since the 1960s. It is closely related to P. incarnata (V. C. Muschner et al. 2003) and will key to this species in this treatment. Passiflora edulis differs from P. incarnata by its larger stipules, at least 10 mm; leaf margins generally more coarsely serrate; larger, leaflike floral bracts, at least 17 × 8 mm; and a broadly and abruptly expanded androgynophore base (gradually expanded in P. incarnata). Passiflora ‘Incense’, an artificial hybrid between P. incarnata and the South American P. cincinnata Masters, also will key to P. incarnata in this treatment. It differs from the latter by consistently having five-lobed leaves with lobes that are much-narrowed basally, and larger floral bracts, at least 15 × 10 mm.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The leaves of Passiflora pallida show variation in lobe number, from juvenile to adult plants, and within and among individuals, with both unlobed and three-lobed leaf forms most common. In Texas, leaves on mature plants are always symmetrically three-lobed; in Florida, leaves can be unlobed, symmetrically three-lobed, or asymmetrically two- to three-lobed. Passiflora pallida is also self-compatible, an unusual feature in the genus.

In peninsular Florida, Passiflora pallida is widespread and locally common to occasionally weedy. In Texas, it is relatively uncommon, known only from the extreme southernmost part of the state and from a single disjunct population about 150 miles northward in Refugio County (S. R. Hill 1981).

Traditionally synonymized under Passiflora suberosa in our region (for example, D. S. Correll and M. C. Johnston 1970; R. L. Hammer 2002; R. P. Wunderlin and B. F. Hansen 2003), P. pallida is closely related to the larger-flowered P. suberosa and commonly is treated as conspecific with it worldwide. The hypanthium of P. pallida generally is 3–4 mm in diameter, with inner coronal filaments usually less than 1.5 mm and outer filaments less than 4 mm, whereas in P. suberosa the hypanthium generally is 4–8.8 mm in diameter, with inner coronal filaments usually 1.5–3.9 mm and outer filaments (2.5–)3–8.1 mm. Passiflora suberosa is native in

Mexico, the West Indies, and Central and South America, and has been widely introduced in tropical regions (weedy in Hawaii), but does not occur in the flora area. In regions where the two species naturally co-occur, P. pallida generally is found at lower elevations than P. suberosa. These two species and close relatives were reviewed by K. E. Porter-Utley (2003).

(Discussion copyrighted by Flora of North America; reprinted with permission.)