Lasianthaea fruticosa (L.) K.M.Becker

  • Authority

    Becker, Kenneth M. 1979. A monograph of the genus Lasianthaea (Asteraceae). Mem. New York Bot. Gard. 31 (2): 1-64.

  • Family

    Asteraceae

  • Scientific Name

    Lasianthaea fruticosa (L.) K.M.Becker

  • Description

    Species Description - Shrubs or rarely half-shrubs woody near base only, (0.3-)0.5-6(-7) m high; young branches glabrous to villous. Leaves with petiole 0.5-7 mm long, glabrous to tomentose; blade thin to firm, ovate to narrowly lance-ovate, (1.5-)3-22 cm long, (0.4-)1-22 cm wide, acute to long-acuminate, rounded to cuneate at base, nearly glabrous to scabrous and hispid above, nearly glabrous to tomentose below, margin denticulate-mucronulate to coarsely serrate, triphnerved, rarely subpenninerved. Inflorescence 3-15-headed, terminal and from upper leaf axils, and solitary from upper leaf axils. Peduncles 0.2-14 cm long, stout to slender, glabrate, hispid, or villous; heads 1.5-3.5 cm wide across extended rays. Involucre campanulate to hemispherical, 0.5-1.4 cm high, 0.4-1.9 cm wide, phyllaries usually subequal, occasionally graduated in 2-3 series. Outer phyllaries membranous-indurate below, herbaceous above, ovate, lanceolate, or oblong in outline, 3.5-16 mm long, 1-8 mm wide, acute to obtuse, glabrous to hirsute dorsally, middle phyllaries often 3-lobed at apex, inner phyllaries ovate to oblong in outline, 5-10 mm long, 1-5 mm wide, acute to rounded. Rays 4-13, yellow, lamina 5.5-20 mm long, 2.4-7.0 mm wide, tube 1.0-4.0 mm long. Disc florets 9-ca. 100, yellow, 4.5-8 mm long, throat campanulate, 4-7.5 mm long, 0.9-1.8 mm wide, lobes 0.5-1.0 mm long. Anther thecae brown to blackish, 1.5-3.1 mm long, appendage (0.3-)0.5-0.9 mm long. Style branches 1.5-3.0 mm long, appendage 0.3-1.0 mm long. Disc achenes cuneate, 2-awned, body 3-6 mm high, 0.9-2.1 mm wide, glabrate, puberulent, or hispidulous, occasionally glandular, awns 1.5-5.5 mm long, pappus squamellae connate and ca. 0.2 mm long, with individual squamellae to 0.8 mm long, or reduced to a ciliate fringe. Ray achenes 3-awned, body 1.5-5 mm long, 1.0-2.3 mm wide, awns 0.5-4(-4.5) mm long, pappus squamellae 0-1.3(-2.3) mm long. Receptacle convex or low-convex.

  • Discussion

    Bidens fruticosa L., Sp. PI. 833, 1753 (based on Bidens foliis ovatis serratis petiolatis, fruticoso. Hort. Cliff. 399, 1737), not Zexmenia fruticosa Rose, Contr. U.S. Nat. Herb. 1: 103, 1891. Verbesina fruticosa L., Sp. PI. ed. 2: 1271, 1763.

    Narvalina fruticosa (L.) Urb., Symb. Ant. 5: 265, 1907. Type: Cultivated in Hort. Cliff, (holotype: BM; photo: NY).

    Lasianthaea fruticosa is a wide-ranging species (Map 1) which has become differentiated into a number of more or less distinctive geographic varieties. Six varieties are recognized here, ranging from northern Mexico to Central America. All are united by their yellow rays, shrubby habit, and a general tendency to non-graduated or weakly graduated involucres. L. fruticosa appears to have a distinctive chromosome number (n = 11, as opposed to n = 10 in the other shrubby Lasianthaeas), and, as discussed below, is rather isolated from the rest of the shrubs with respect to hybridization.