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.)

Passiflora tarminiana is sparingly naturalized in the eastern San Francisco Bay area (F. Hrusa et al. 2002) and southward along the coast to San Luis Obispo County, in areas of minimal summer drought.

This species was recently described, and is commonly confused with Passiflora mollissima (Kunth) L. H. Bailey [now usually recognized as P. tripartita var. mollissima (Knuth) Holm-Nielsen & P. Jørgensen]. Many reports of P. mollissima in agricultural, horticultural, and weed-science literature actually apply to P. tarminiana. An attractive plant with large, edible fruits (T. Ulmer and J. M. MacDougal 2004), it is an extremely aggressive weed in Hawaii (A. M. La Rosa 1984, as P. mollissima) and other areas where it has been introduced in the Old World tropics and subtropics. The species is unlikely to become a widespread weed in the continental United States because it cannot survive frost nor occasional desiccation.

A similar, closely related species, Passiflora mixta Linnaeus f., is a rare escape in San Francisco, California; it can be distinguished from P. tarminiana by its angular young stems, persistent stipules (deciduous in P. tarminiana), and a floral tube 80–110 mm deep, 1.6–2.6 times the sepal length (1.3–1.6 times in P. tarminiana).

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