Ludwigia litoranea Cocco & Boldrini, 2015

Pesamosca, Silviane Cocco & Boldrini, Ilsi Iob, 2015, Ludwigia litoranea (Onagraceae), a new species from coastal southern Brazil, Phytotaxa 230 (2), pp. 183-188 : 183-185

Ludwigia litoranea Cocco & Boldrini , sp. nov. ( Figures 1 and 2 )

Ludwigia litoranea differs from L. grandiflora , by its narrowly linear stipules (versus ovate), and from L. hookeri by its stipules and bracteoles narrowly linear with a glandular ovoid, apex (vs. fusiform) and by stipels that are similar to bracteoles (vs. deltate).

Type:— BRAZIL. Rio Grande do Sul: Tavares, turfeira localizada no Parque Nacional da Lagoa do Peixe, WGS-84, 31º15’8.0’’S, 50º59’21.7’’W, 14 m alt., 22 January 2015, S.P. Cocco & L. Oliveira 464 (holotype ICN!, isotypes P!, MO!, RB!).

Herbs or subshrubs, perennial, 28–40 cm high, procumbent, rhizomatous or erect. Stems subcylindric, green to brown, pubescent, nodes with abundant fascicles of axillary leaves, 2–6 × 0.3–1.5 mm. Stipules narrowly linear with a glandular apex, ovoid, succulent, green to brown, 1–1.5 × 0.1–0.2 mm. Leaves sessile, entire, membranaceous, puberulent to villous, the blades 8–28 × 3.5–5 mm, oblong, oblanceolate to obovate, ciliate and glandular along margin, acute at base, obtuse to rounded at apex, abruptly mucronate and glandular, the gland ovoid; with 5–9 veins on each side of midvein, prominent on the abaxial face, tertiary veins anastomosing and inconspicuous, submarginal vein prominent. Bracts similar to other leaves, gradually reduced distally. Pedicels 3–17 mm long. Flowers solitary, axillary. Bracteoles 2, borne at base of ovary, narrowly linear with a glandular apex, ovoid, deciduous or not, succulent, green to brown, 1–1.5 × 0.1 mm, subtended by a pair of persistent stipels, 0.4–0.5 × 0.1 mm, narrowly linear with a glandular apex, ovoid. Sepals 5, lanceolate, acute or acuminate at tip, green, puberulent on the abaxial face, 3.5–7.5 × 1.2–2 mm, 1–3-nerved. Petals 5, yellow, obovate, acute or slightly unguiculate at base, orange, slightly emarginate at apex, 8–15 × 5–10 mm. Stamens 10, unequal, the episepalous are the longest, filaments 2.5–3 mm, anthers 1–1.5 × 0.5–1 mm, oblong, the epipetalous are the shortest, filaments 2–2.5 mm, anthers 0.5–1 × 0.5–1 mm, oblong. Ovary cylindric, 5- angled or subterete, puberulent, 4–5 × 1 mm. Disk plane, ca. 0.3 mm high, pubescent at the base of each epipetalous stamen. Style 3–4 mm long; stigma capitate, subglobose, 0.5 × 0.5–1 mm. Capsule subterete, narrowed at both ends, 5-angled, green to deep-brown, puberulent, 5–10 × 2.5–3.5 mm. Seeds 8–10 per locule, uniseriate, enveloped in a very thin wedge-shaped piece of endocarp, elliptic or rhombic, white to light-brown, striate, bright, 0.8–1 × 0.6–0.8 mm; raphe very narrow.

Distribution and habitat:— Ludwigia litoranea occurs in the southern Brazilian states of Rio Grande do Sul and Santa Catarina ( Figure 3 ). It is restricted to the coastal areas, between 10 and 14 m elev., growing in fens on Planossoils. Soils in the region were formed in the Quaternary and are composed predominantly of sandy sediments ( Villwock & Tomazelli 1998).

Etymology:—The specific epithet refers to the habitat in coastal areas.

Phenology:—Flowering and fruiting occur from November to February.

Conservation status:—The new species is known only from three locations, one in Rio Grande do Sul (Parque Nacional da Lagoa do Peixe) and two in Santa Catarina, where it has been collected about 30 years ago. Currently, their habitat has been greatly reduced because many southern coastal areas are under intense anthropogenic pressure due to urbanization, rice crop, pinus and eucalyptus afforestation and pinus invasion. In addition, it presents a small area of occupancy <10 km 2 (AOO 3 km 2) and a reduced population with about 50 mature individuals resulting in the assessment of the Critically Endangered category. Associated with this information, Ludwigia litoranea occurs in a very specific habitat then these populations monitoring is strongly recommended. Therefore, this species is here considered as Critically Endangered – CR B2ab (ii,iii,iv,v) according to the IUCN Red List of Threatened Species.

Paratypes:— BRAZIL. Rio Grande do Sul: Tavares, Parque Nacional da Lagoa do Peixe, 31º15’8.0’’S, 50º59’21.7’’W, 14 m alt., 22 January 2015, S. P. Cocco & M. G. Facco 377 (ICN!, PACA!, MBM!, FLOR!, K!). Santa Catarina: Araranguá, Morro dos Conventos , 17 November 1971, J. C. Lindeman s.n. (ICN 9149!) ; Passo de Torres , 9 January 1983, K. Hagelund 14425 (ICN!) ; February 1987, K. Hagelund s.n. (ICN 83773!).

Figures

FIGURE 1. Ludwigia litoranea Cocco & Boldrini (from the S.P. Cocco & L. Oliveira 464). A. Habit. B. Flower. C. Petal. D. Capsule. E. Bracteole and stipels. F. Capsule cross section. G. Endocarp. H. Seed. I. Leave apex. J. Stipules. K. Leave and abundant fascicles of axillary leaves. A (5 cm). B–D (2 mm). E–K (1 mm). (Drawn by Anelise Scherer).

FIGURE 2. Ludwigia litoranea Cocco & Boldrini. A. Flowers. B. Habit. C. Habitat.

FIGURE 3. Distribution of Ludwigia litoranea Cocco & Boldrini in southern Brazil.