Lasianthaea ceanothifolia var. gracilis (K.M.Becker) W.W.Jones

  • 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 ceanothifolia var. gracilis (K.M.Becker) W.W.Jones

  • Description

    Species Description - Shrubs, slender-stemmed and loosely branching, 1-3 m high; young branches sparsely strigose. Leaves with petiole 0.5-1(-1.5) cm long, its margin usually hispid, otherwise strigose; blades thin, usually lance-ovate, varying to lanceolate and ovate, occasionally somewhat falcate, 5-13 cm long, 2-5 cm wide, acute and acuminate, cuneate at base, scabrous with sparse, appressed hairs above, hirsute below, especially along veins, margin often ciliate, serrate, triplinerved. Peduncles to 5 cm long, usually slender, strigose, often white-pilosulous when young. Involucre cylindro-campanulate to broadly campanulate, 0.6-1.1 cm high, 0.3-1.0 cm wide, phyllaries graduated in 4-6 series. Outer phyllaries ovate to broadly ovate in outline, 2-4(-8) mm long, 2-5 mm wide, white-strigose, strigiHose, or glabrate dorsally, becoming conspicuously parallel-nerved inwards, inner phyllaries often 3-lobed at apex, 0.6-1.0 cm long. Rays typically 8, lamina 6-10 mm long. Disc florets 8-30, 6.5-8 mm long. Disc achenes with body 4-4.5 mm long, 1-1.2 mm wide, awns 3-6 mm long, exserted 1-3(-4) mm from ripe heads.

  • Discussion

    Zexmenia gracilis "W. W. Jones, Proc. Amer. Acad. 41: 154, 1905. Type: MEXICO: Colima: Colima, Aug 1897, Palmer 163, coll of 1897 (holotype: US; isotypes: C, MICH, S). Zexmenia rotundata Blake, Contr. U. S. Nat. Herb. 22: 632, 1924. Type: MEXICO: Durango: Huasemote, 14 Aug 1897, Rose 3478 (holotype: US). Lasianthaea ceanothifolia var. gracilis in the most distinctive variety of L. ceanothifolia. It occurs mostly on the Pacific slope in southern Sinaloa and Nayarit, and tends to prefer moist wooded habitats. It is characterized by its strongly and conspicuously nerved middle and outer phyllaries, which are usually green and often glabrous, its slender branches, and its generally sparse pubescence. There appears to be a phenological differentiation between var. gracilis and var. verbenifolia in Nayarit, the former tending to bloom earlier (August-September), the latter later (October-December). Plants of this variety from western Michoacan (e.g., Hinton 15157) tend to have larger heads (ca. I cm wide) than plants from farther east. Interactions involving apparent hybridization between L. ceanothifolia and L. helianthoides, L. macrocephala, L. crocea, and L. fruticosa are discussed under those species.

  • Distribution

    Roadcuts, mountainsides, stream vaHeys in moist tropical forest and tropical deciduous forest. Southern Sierra Madre Occidental and western Transverse Volcanic Belt in west-central and southwestern Mexico (Map 4), also in low-lying coastal areas, at altitudes from 70-1250 m . Blooming August to October.

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