Bacopa paraguariensis (Moore) Hassler (1917: 13)

Sosa, María De Las Mercedes, Moroni, Pablo & O’Leary, Nataly, 2018, A taxonomic revision of the genus Bacopa (Gratioleae, Plantaginaceae) in Argentina, Phytotaxa 336 (1), pp. 1-27 : 11

6. Bacopa paraguariensis (Moore) Hassler (1917: 13) . Fig. 6 .

≡ Herpestis paraguariensis Moore (1895: 407) .

Type:— PARAGUAY. Caaguazú, 1876, B. Balansa 2142 (holotype K 000533457!).

Herbs, perennial, 35–80 cm tall, prostrate stems with stout erect branches, puberulous. Leaves opposite, sessile, blade oblong or narrow ovate, 20–45 × 5–10 mm, apex acute, base auriculate, margin entire exceptionally slightly serrate, glabrous or slightly puberulous. Flowers axillary, solitary or 2 per axil, pedicel 4–20 mm long, bracteoles two, linear, 0.8–1 mm long, puberulous. Calyx 5-lobed, the external dorsal lobe ovate, 4–6 × 1.8–2 mm, apex acute, base truncate, the two lateral lobes ovate, 4.9–5 × 1.8–2 mm, apex acute, base acute, glabrous or slightly puberulous, the two internal lobes linear, 4.8–5.2 × 0.8–1.2 mm, apex acute, glabrous or slightly puberulous. Corolla lilac, tube 7–8 mm long, puberulous; stamens 4; ovary glabrous, style entire, stigmatic apex bilobed. Capsule globose, apex rounded, 2.8–3 × 2.8–3.2 mm.

Distribution and habitat:—Native from South America, it is found in Paraguay and northern Argentina in the provinces of Chaco, Corrientes, Formosa and Misiones. It grows between sea level and 500 m elev.

Taxonomic remarks:— Bacopa paraguariensis could be confused with B. monnierioides (Cham.) Rob. (see remarks under this last species). It is also very similar to B. scabra var. scabra . However, they are distinguished because leaf blades are oblong or narrow ovate with auriculate base, and bracteoles are ca. 1 mm long in B. paraguariensis , vs. ovate leaf blades, with acute base, and bracteoles longer, 3 – 4 mm long in the latter.

Selected specimens examined:— Chaco: Primero de Mayo, Col. Benítez, Jan 1935, Schulz 1582 (CTES). Corrientes: Concepción, Carambola, 20 Mar 1987, Pedersen 14850 (BAB, CTES). Formosa: Guaycalee, 1919, Jorgensen 2997 (LIL). Misiones: Cainguás, Scharwz 6680 (LIL).

Figures

FIGURE 6. Bacopa paraguariensis. A. Plant aspect. B. Flower. C. Corolla opened, showing stamens. D. Gynoecium. E. Calyx. F. Detail of bracteoles. G. Fructiferous gynoecium. H. Dorsal lobe, external view. I & J. Lateral lobes, external views. K & L. Internal lobes (from Pedersen 14850, CTES).