Bacopa cladostyla Eskuche (1989: 11)

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 : 11-14

7. Bacopa repens (Swartz) Wettstein (1895: 76) . Fig. 7 .

≡ Gratiola repens Sw. (1788: 14) ≡ Herpestis repens (Sw.) Schlechtendal & Chamisso (1830: 107) ≡ Herpestis obovata Poeppig. ex Chamisso & Schlechtendal (1830: 107) pro. syn. ≡ Macuillamia repens (Sw.) Pennell (1923: 9) .

Type:— JAMAICA. Jun. 1786, O. P. Swartz s.n. (lectotype S 04-341! [designated here], isolectotypes BM 000953377!, LINN-HS No. 48-3!, LD 1741638!, S-R-2471!, S-R-2470!).

= Macuillamia limosa Pennell (1920: 158) ≡ Bacopa limosa (Pennell) Standley (1925: 460) .

Type:— COLOMBIA. Cundinamarca: Melgar, open pool in clayey loam, alt. 400 – 500 m, F.W. Pennell 2927 (holotype NY 00090653, isotypes CAS 0003270!, PH 00016463!, US 00122518!).

= Bacopa cladostyla Eskuche (1989: 11) , syn. nov.

Type:— PARAGUAY. San Bernardino, campo estero Ciervo-cuá, Feb 1915, T. Rojas 1043 (holotype LIL 222.457!, isotypes LIL 70.170 ex Hb. Gray!).

Herbs, annual, 3–5 cm tall, prostrate, ascending stems, strigose. Leaves opposite, sessile, blade ovate elliptic, 6–8 × 5–7 mm, apex rounded, base rounded, margin entire, adaxial surface glabrous, abaxial surface sparsely pubescent, more densely on the veins. Flowers axillary, solitary, pedicels 1–2(–5) mm long, villose; bracteoles absent. Calyx 5- lobed, the external dorsal lobe wide ovate, 2–4 × 2–2.8 mm, apex rounded, base cordate, the two lateral lobes ovate, 2–3 × 1.3–2 mm, apex obtuse, base cordate, strigose towards the apex and in the central vein, the two internal lobes linear, 2–4 × 0.4–0.6 mm, apex acute, hispid on margins and veins. Corolla white, tube 2.5–3 mm long, puberulous; stamens 2 plus 1 or 2 staminodes; ovary glabrous, style deeply bifid, stigmatic apex hairy globose. Capsule ovoid, apex acute, 2.8–3 × 2.2–2.5 mm.

Distribution and habitat:— Bacopa repens is found growing from the United States of America to Argentina, in the northeastern provinces of Corrientes, Formosa and Santa Fe. It is also frequent in China ( Deyuan et al. 1998). It grows between sea level and 500 m elev.

Nomeclatural remarks:— Swartz (1788) described Gratiola repens from material collected in Jamaica.According to Christenhusz (2011) the holotype is at S, where most of Swartz’s collections from the West Indies are housed ( Stafleu & Cowan 1986, Pupulin 2009). However, three sheets that can be undoubtedly attributed to Swartz were located there. Souza & Giulietti (2009: 54) lectotypified this name on a Bertero specimen from Jamaica although this element cannot be considered original material for the name since Swartz based the Prodromus on his own collections and those in the Banksian herbarium ( Nicolson & Jarvis 1990). Therefore, Souza & Giulietti’s designation is not in conformity with Art. 9.12 and must be superseded. Among the original material at S there is a specimen annotated in Swartz’s handwriting: “ Gratiola repens 1786 Jamaica ”. Thus, this specimen is here selected as lectotype of the name.

Taxonomic remarks:—The analysis of the type material of B. cladostyla , together with the description in the protologue evidences that it is a synonym of B. repens .

The presence of two stamens, instead of four, differentiates B. repens from the rest of the Bacopa that grow in Argentina. See remarks under B. australis .

Selected specimens examined:— Corrientes: Itatí, arrocera Repeczki, 28 Feb 1977, Ahumada et al. 891 (CTES). Formosa: Arrocera Sur. Establecimiento Negra-í, RN 11, km 1251, 20 Jan 2000, Iriart 577-8b (CTESN). Santa Fe: San Javier, 8 Feb 2000, Iriart 604-14ª (CTESN).

Figures

FIGURE 7. Bacopa repens. A. Plant aspect. B. Detail of stem pubescence. C. Detail of node. D. Flower. E. Corolla opened, showing stamens. F. Gynoecium. G. Calyx with dorsal lobe opened. H. Fructiferous gynoecium. I. Dorsal lobe, external view. J & K. Lateral lobes, internal views. L & M. Internal lobes (from Eskuche 3454, CTES).