Justicia chamaecaulis 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

publication ID	https://doi.org/10.3897/phytokeys.258.144435
DOI	https://doi.org/10.5281/zenodo.15676461
persistent identifier	https://treatment.plazi.org/id/A1B8041D-BFE4-5482-8481-E1F94D1D7361
treatment provided by	PhytoKeys by Pensoft
scientific name	Justicia chamaecaulis J. R. I. Wood & R. Villanueva
status	sp. nov.

Treatment

8. Justicia chamaecaulis J. R. I. Wood & R. Villanueva sp. nov.

Type.

Peru • Loreto, Maynas, Dist. San Juan Bautista, Peñanegra, 8 km de Iquitos , 19 Aug. 1976, F. Encarnación 927 (holotype K-000544765 , isotypes US-2956902 , USM)

Diagnosis.

Low herb, <10 cm high, the short dense inflorescence usually with several spikes and calyx 5 - lobed; somewhat similar to some forms of Justicia potarensis (Bremek.) Wassh. in leaf shape, indumentum and pilose inflorescence but always <10 cm high (not up 40 cm), the spikes 1–4 cm long (not 5–15 cm long), flowers densely imbricate (not clearly separated) and the bracts equalling or longer than the calyx (not shorter).

Description.

Small leafy herb <10 cm high from a slender taproot with fibrous lateral branches; stem usually simple, villous with stiff white hairs. Leaves crowded below inflorescence, the internodes up to 12 mm, but usually much less, petiolate, lamina 1.5–7 × 1–2 cm, oblong-elliptic, apex obtuse, adaxially thinly pilose to glabrescent except pubescence along the mid vein, abaxially slightly paler, glabrous except for pubescence on the mid vein above petiole, punctate; petioles 3–13 mm, villous. Inflorescence of solitary terminal bracteate spikes, sometimes with a secondary spike from uppermost leaf axil; spikes 1–4 cm long, sessile, the flowers imbricate, bracts 9 × 2.5 mm, oblanceolate, obtuse, green with prominent veins, thinly pilose; bracteoles 8.3–13 × 1.25 mm, thinly pilose, oblanceolate; calyx 5 - lobed to near base, lobes linear-filiform, attenuate, slightly unequal in width, 6–7 × 0.25–0.5 mm, thinly pilose; corolla c. 8 mm long, 2 - lipped, tube c. 4 × 1.5 mm, white; lips purplish, upper lip lanceolate, notched; lower lip 4–5 × 5 mm, 3 - lobed, the lobes rounded, thecae oblong, 1 × 0.25 mm, glabrous, strongly superposed, the lower with a basal appendage; pollen prolate, 38–41 × 23–26 μm, 3 - aperturate (possibly 4 - aperturate), colporate, a row of unbroken band of sexine on either side of aperture (Fig. 49 A View Figure 49 ); style pilose. Capsule 7–8 × 2 mm, clavate, pubescent, 4 - seeded; seeds 1.5 mm diam., rugose.

Illustration.

Fig. 11 K – S View Figure 11 .

Etymology.

The name “ chamaecaulis ” meaning ‘ low stem’ refers to the low growing habit so characteristic of this plant.

Phenology.

Found in flower in February, July, August, and September.

Habitat.

Forest clearings and tracksides on white sand at low altitudes, 140– 150 m.

Distribution.

Endemic to Peru and only known from the Iquitos area of Maynas in Loreto. Fig. 65 View Figure 65 .

Material examined.

Peru • Loreto: Prov. Maynas, Río Nanay, halfway between Santa María de Manay and Iquitos , 3°30'S, 73°30'W, 140 m, 23 Feb. 1981, Al. Gentry et al. 31643 ( MO, US) GoogleMaps ; • ibid., Dist. Iquitos, trail from Picuru ( lower Río Maynas ) to Río Mazan , S. McDaniel 21463 ( US); Dist. San Juan Bautista , carretera Pena Negra a 7 km de Quisto Cocha, Río Itaya , 150 m, 18 Sept. 1981, M. Rimachi 5713 ( US) GoogleMaps ; • ibid., 8 km de Iquitos, 19 Aug. 1976, F. Encarnación 927 (K, US, USM) GoogleMaps ; • ibid., Quistococha, vic. Iquitos , 140 m, 16 Nov. 1977, Al. Gentry 20723 ( MO, US, USM) GoogleMaps ; • ibid., Mishana, trail from village to Camp. 1, 3°50'S, 73°30'W, 140 m, 22 July 1980, Al. Gentry et al. 28936 ( MO) GoogleMaps ; • ibid., Dist. Alto Nanay, Santa María de Nanay, Mishana ( Río Nanay ), 5 Aug. 1990, R. Vásquez et al. 14167 ( MO) GoogleMaps .