Bacopa monnieri (Linnaeus) Wettstein, 1895

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 : 8-9

4. Bacopa monnieri (L.) Wettstein (1895: 77). Fig. 4 .

≡ Lysimachia monnieri Linnaeus (1756: 9) ≡ Gratiola monnieri Linnaeus (1759: 851) . ≡ Capraria monnieria (L.) Roxburgh (1814: 47) ≡ Herpestis monnieria (L.) Kunth (1818: 366) ≡ Bramia monniera (L.) Drake (1893: 142) ≡ Monniera monniera (L.) Britton (1894: 292) nom. inv. ≡ Bramia monnieri (L.) Pennell (1919: 243).

Type:— Browne (1756) t. 28, f. 3 [lectotype, designated by Cramer (1981: 421)].

= Bramia indica Lamarck (1785: 459) .

Type:—[LOCATION UNKNOWN], P-LA! (lectotype P 00357973! [designated here]).

Herbs, annual or perennial, 10–20 cm tall, prostrate, glabrous. Leaves opposite, sessile, blade obovate, 5–14 × 2–5 mm, apex obtuse, base acute, margin entire, glabrous. Flowers axillary, solitary, pedicels 10 – 20 mm long, bracteoles two, linear, 2–3 mm long, glabrous. Calyx 5-lobed, the external dorsal lobe ovate, 4.8–5 × 2.5–3 mm, apex rounded or acute, base truncate, the two lateral lobes ovate, 5 × 2 mm, apex acute, base truncate, glabrous, the two internal lobes linear, 4.8–5 × 0.8–1 mm, apex acute, glabrous. Corolla white, blue or lilac color, tube 7–8 mm long, glabrous; stamens 4; ovary glabrous, style entire, stigmatic apex globose. Capsule ovoid, apex acute, 3.5–3.8 × 1.8–2 mm.

Distribution and habitat:— Bacopa monnieri is the most widely distributed species of the genus, present in all the continents, with the largest number of collected specimens in tropical and subtropical America. In Argentina it is found in Chaco and Salta at 400 m elev., to the Prepuna at 3500 m elev. and down towards Tierra del Fuego province. It frequently forms grass in moist, sandy or marshy soils.

Nomenclatural remarks:— Lamarck (1785) in the protologue of Bramia indica mentioned a new nomen specificum legitum citing two synonyms: the first one from Rheede (1690: 27), and the other one from Commelijn (1696: 33). The author also mentioned that he had studied a dried specimen (v. s.) to describe the species. Lamarck’s types are mainly kept at P-LA ( Stafleu & Cowan 1979) and so original material of the name should be there. Indeed a specimen in agreement with the diagnosis and annotated by Lamarck was located at P-LA.As specimens are preferable to illustrations, this specimen is selected as lectotype of the name.

For a discussion on the complex nomenclature of the species see Philcox (1979).

Taxonomic remarks:— Bacopa monnieri is easily distinguished being the only Argentine Bacopa that is entirely glabrous, and has obovate leaf blades.

Selected specimens examined:— Buenos Aires: Pdo. De la Costa, San Clemente del Tuyú, Punta Rasa, 22 Jan 1979, Tur 1693 (CTES, SI). Catamarca: Ambato, Valle Río Los Puestos, 29 Feb 1996, Saravia Toledo 13785 (CTES). Chaco: Libertad, Col. Popular, 28 Nov 1967, Schulz 16237 (CTES). Córdoba: Río Cuarto, 19 Apr 2011, Keller 10179 (CTES). Corrientes: San Martín, Carlos Pellegrini, 30 Oct 1971, Krapovickas et al. 20298 (BAB, CTES). Entre Ríos: Concordia, 7 Sep 1978, Neiff 890 (CTES). Formosa: Pilcomayo, 24 Oct 1995, Schinini 30296 (CTES). Jujuy: Santa Bárbara, 11 Feb 2010, Zuloaga 11544 (CTES, SI). La Rioja: Chamical, 20 Feb 2000, Biurrun 6399 (CTES). Mendoza: Las Heras, El Callao, Ruiz-Leal 8410 (BAB, LIL). Neuquén: Huiliches, Pampa del Malleo, Jan 1996, Martínez-Crovetto AN-44 (CTES). Salta: Rivadavia, La Merced Vieja, 25 Dec 2002, Scarpa 496 (CTES, SI). Santiago del Estero: Pellegrini, río Urueña, Venturi 5657 (BAB, LIL). San Juan: Ullum, 1 Dec 1985, Kiesling 5060 (CTES). San Luis: Junín, Bajo de Véliz, Kurtz 8459 (CORD). Tierra del Fuego: San Sebastián, Río Grande, Castellanos (BA 45746). Tucumán: Tafi, 25 Mar 1989, Pedersen 15335 (CTES).

Figures

FIGURE 4. Bacopa monnieri. A. Plant aspect. B. Detail of rooting node. C. Detail of node with two leaves. D. Flower. E. Corolla opened, showing stamens. F. Gynoecium. G. Bracteoles. H. Dorsal lobe, external view. I & J. Lateral lobes, external views. K & L. Internal lobes (from Schinini 19195, CTES).