Alternanthera halimifolia
Content
Description
Woody shrub or herb, to 2 m; stems erect to sprawling and spreading, few-branched; indument on young stems, leaf-veins and inflorescence-axes often yellowish-brown or whitish, densely velutinous with basally branched or stellate hairs, glabrescent with age. Petiole 2-10 mm long; blade mostly narrowly lanceolate or elliptical, sometimes ovate or orbicular, 1-5 x 0.5-2.5 cm, apex obtuse or acuminate, mucronate, cuneate at base. Inflorescence of axillary, sessile, heads; heads ovoid, 4-12 x 3-5 mm; bracts and bracteoles erect, white, hyaline, subequal, broadly ovate to elliptical, 1.4-2.3 mm, acuminate to aristate, pubescent with minutely retrorsely barbed hairs. Tepals erect, dimorphic, outer 3 tepals broader, rigid, ovate to elliptical, 2.6-5.0 mm long, (1-)3-veined, acuminate, mucronate, brown to green below, becoming white above, hispidulous at base with retrorsely barbed hairs, inner 2 tepals shorter, conduplicate, hyaline, sparsely to densely pubescent along fold; stamens 5, anthers oblong, pseudostaminodia exceeding stamens, apically fimbriate or lacerate; stigma capitate. Utricle globose or ovoid, 1.0-1.5 mm; seed reddish-brown, cochleate-orbicular or lenticular, 0.8-1.1 mm wide.
Distribution
Circumcaribbean present, Guianas present
Circumcaribbean; often in coastal areas; 41 collections studied, all from the Guianas (GU: 27; SU: 11; FG: 3).
Notes
Kellogg (1988: 154-155) suggests this species might be better treated as a variety of A. ficoidea (for which the name A. tenella still is used), and gives a detailed discussion of its difficult complex, which has four elements occurring in large areas of South America; she includes a table showing the characteristics of certain French Guiana and Suriname variants. The indumentum of this species has been variously characterized as velutinous or sericeous.