Justicia lactiflora J. R. I. Wood & R. Villanueva, 2025

Villanueva-Espinoza, Rosa, Deng, Yunfei, Scotland, Robert & Wood, John R. I., 2025, Preliminary notes on Justicia (Acanthaceae) in Peru, PhytoKeys 258, pp. 1-123 : 1-123

39. Justicia lactiflora J. R. I. Wood & R. Villanueva sp. nov.

Type.

Peru • Ucayali, Prov. Padre Abad, Pucallpa – Tingo María road, km 139, Puente Chio , 10 Sept. 1980, P. J. M. Maas et al. 4554 (holotype US-2949117 , isotypes K-000544763 , U, USM) .

Diagnosis.

Clambering shrub similar in habit to Justicia scansilis and J. pyrrhostachya , differing most clearly from the former by the greenish lanceolate bracts up to 3 mm wide (not ovate, reddish, 2–2.5 × 1.5–2.5 cm) and from the latter by the white or whitish flowers (not red or orange-red) and the membranous (not scarious) bracts only c. 12–15 × 3 mm (not more than 15 × 10 mm).

Description.

Isophyllous clambering shrub 1–8 m in height; stems woody below, bifariously hirtellous. Leaves petiolate, lamina 4–13 × 1.2–5.3 cm, ovate to oblong-ovate, acuminate, base broadly cuneate, both surfaces puberulent when young soon glabrescent, abaxially paler, minutely punctate, lateral veins 6 pairs; petioles 0.3–1.7 cm, puberulent. Inflorescence of pedunculate axillary and terminal, foliose, cymose capitula; primary peduncles to 3 cm long, bifariously puberulent; pedicels 0–0.9 mm, puberulent; bracts 12 × 3 mm, lanceolate, pubescent; bracteoles similar but only c. 1–2 mm long; calyx 5 - lobed, lobes 10–11 × 2.5–3 mm, lanceolate, acuminate to a very acute apex, minutely pubescent; corolla c. 3 cm long, white, variously suffused with purple, the veins prominent, thinly pubescent, upper lip hooded c. 10 × 12 mm, ovate, emarginate, lower lip broadly ovate to suborbicular, c. 20 × 20 mm, very shallowly 3 - lobed, lobes c. 1 × 2–3 mm; filaments glabrous, anther thecae 2 × 1.5 mm, superposed, parallel, pubescent, shortly oblong, lower with white basal appendage; pollen prolate, 46–47 × 29 μm, 2 - aperturate, colporate, 1 row of c. 7–8 peninsulae on either side of aperture (Fig. 51 F ); ovary pilose, style pilose. Capsule and seeds not seen.

Illustration.

Fig. 39 .

Etymology.

The epithet “ lactiflora ” refers to the distinctive milk-white corollas of this species.

Phenology.

Found in flower principally between August and October with a few sporadic records from other months.

Habitat.

Primary tropical forest on alluvial soil, often in scrub along river banks, 100–470 (– 1000) m.

Distribution.

Endemic Amazonian Peru and restricted to Loreto and Ucayali. Fig. 68 .

Material examined.

Peru. Loreto: Prov. Maynas, Punchana near Iquitos , 100 m, 7 April 1948, R. Ferreyra & H. J. Corner 3346 ( MOL, US, USM) ; • ibid., Dist. Iquitos , 100 m, Aug. 1929, E. P. Killip & A. C. Smith 27471 (F, US) ; • ibid., Explorer’s Inn, near Indiana, Río Amazon below Iquitos , 130 m, 3°30'S, 73°3'W, 15 Feb. 1989, Al. Gentry et al. 65850 ( MO) . Ucayali: Prov. Coronel Portillo [General Portillo], entre Sinchono y Boquerón, hacia Pucallpa , 1000–1100 m, 15 Aug. 1946, R. Ferreyra 1107 ( US, USM). Prov. Padre Abad, the type collection ; • ibid., Dist. Padre Abad, Aguaytía , 180 m, 26 Aug. 1946, F. Woytkowski 34443 (F) ; • ibid., Pampa Yurac , 300 m, 9 Sept. 2004, J. Schunke V. & J. G. Graham 15882 ( MO, US) ; • ibid., Aguaytía , 9°05'S, 75°32'W, 28 Sept. 2004, J. Schunke V. & J. G. Graham 16107 (F, MOL, US) ; • ibid., Previsto, Río Yurac , 420 m, 16 Oct. 1962, F. Woytkowski 7610 ( US, MO) ; • ibid., Boquerón de Padre Abad, along Río Chino , 300 m, 8 Aug. 1946, F. Woytkowski 34339 (F, MO) ; • ibid., 470 m, 8 Aug. 1946, F. Woytkowski s. n. ( USM 72643 ) .

Note.

The corolla is variously reported as white or white with various types of purple markings, but it is unclear whether this is because the corolla varies in colour from plant to plant or at various stages of its development.

Figures

Figure 39. Justicia lactiflora A habit B detail of bract indumentum C bract D bracteole E calyx F corolla G anther H ovary and style base. Drawn from J. Schunke Vigo & J. G. Graham 16107 by Margaret Tebbs.

Figure 51. Pollen images A Justicia warmingii (Villanueva 920) B J. werffii (Van der Werff 15565) C J. schunkei (Schunke 7599) D J. spathuliformis (Villanueva 1028) E J. saccata (Villanueva 997) F J. lactiflora (Woytkowski 34339). Scale bars: 10 μm.

Figure 68. Distribution of Justicia oxapampensis (yellow triangles), J. lactiflora (red circles) and J. huallagensis (light blue square) in Peru.