Launaea intybacea (Jacq.) Beauverd

  • Authority

    Acevedo-Rodríguez, Pedro & collaborators. 1996. Flora of St. John, U.S. Virgin Islands. Mem. New York Bot. Gard. 78: 1-581.

  • Family

    Asteraceae

  • Scientific Name

    Launaea intybacea (Jacq.) Beauverd

  • Description

    Species Description - Erect annual or biennial herb to 1 m tall; stems simple or branched, glabrous. Leaves 5-28 x 1.5-11 cm, membranous, the apex acuminate, the margins deeply or shallowly toothed, often purple on lower surface; lower ones ovate to oblanceolate, clustered, with a long-attenuate winged petiole; upper leaves lanceolate, spread along stem, sessile and clasping. Inflorescence with heads solitary or few in a cluster, these short-pedunculate. Heads 15-35-flowered; involucre pyriform to narrowly cylindrical, 10-12 mm high; involucral bracts scariously marginate, the outer ones small and ovate, the inner ones linear-lanceolate, 2-3 times larger than the outer ones; corollas bright to pale yellow, 8-9 mm long. Achenes dimorphic, inner ones more or less cylindrical, outer ones flattened, linear, 4-5 mm long, longitudinally grooved, warty, somewhat constricted at the apex into a weak beak; pappus of numerous white bristles ca. 7-9 mm long, some bristles hairlike, thereby resulting in an obscurely dimorphic pappus.

  • Discussion

    Common name: wild lettuce.

    Note: This species is difficult to place generically because it has characteristics of both Lactuca and Launaea and because both of these genera partly overlap with Sonchus. All the specimens of this species that we examined lacked ascending hairs on the achene margins. Therefore we have followed Jeffrey (1966) and provisionally retained this species in Launaea, although some achenes are compressed and the pappus is not strongly dimorphic. This species is often treated in New World floras as Lactuca.

  • Distribution

    Occasional in open dry areas, usually along sandy coasts. Cruz Bay (A2346), Chocolate Hole (A4067), East End (A684). Also on St. Croix, St. Thomas, and Tortola; a pantropical and subtropical weed of lowland areas.

    Tortola Virgin Islands South America| Saint Thomas Virgin Islands of the United States South America| Saint Croix Virgin Islands of the United States South America|