Justicia impar J.R.I.Wood & P.Gallego, 2023

P. C., Gallego, Wood, J. R. I. & American, South, 2023, Anisophylly in South American Acanthaceae, Rheedea 33 (4), pp. 221-245 : 237-240

Justicia impar J.R.I.Wood & P.Gallego , sp. nov. Fig. 9

A very strongly anisophyllous plant close to Justicia tarapotensis but differing in the oblong-elliptic, acute, pilose, membranaceous bracts (not oblong, obtuse, glabrous to minutely ciliolate, rigid in texture) and subsessile (not distinctly pedunculate) spikes and pubescent (not glabrous) capsule. It somewhat resembles Justicia riopalenquensis in the shape of the bracts and calyx but is strongly anisophyllous, the leaves tapering to a cuneate base (not weakly anisophyllous and rounded at base), peduncles short, 0–1 cm (not 1.5–4.5 cm long), bracts 5–7 mm long (not 3–4 mm), the spikes relatively short and stout, 10–20 × 10–15 (not 25– 40 × 6–9 mm).

Type: PERU, San Martin, Mariscal Cáceres, 2 km del caserío de Nuevo Progreso, carretera a Río Uchiza , S 8°27’04”, W 76°19’33”, 500 m, 23.06.1969. J. Schunke V. 3215 (holo F!; iso K!, US!, USM!) .

Perennial herbs. Stems decumbent and rooting, weakly zigzag, crisped-pubescent; flowering branches ascending reaching 40 cm in length, sparingly branched. Leaves very unequal; larger leaves 3–4 × 0.8–2 cm, oblong-elliptic, base cuneate, somewhat oblique, apex shortly acuminate, obtuse, paler beneath glabrous except puberulent veins; smaller leaves 1–1.5 × 0.7–1 cm, broadly ovate, obtuse, base oblique, truncate. Petioles 2–6 mm long, puberulent. Spikes terminal, usually solitary, 1–2 cm long; flowers imbricate; peduncles 0–10 mm long. Bracts 6–9 × 2–3 mm, narrowly rhomboid to oblong-elliptic, acute, membranaceous, thinly pilose. Bracteoles c. 4 × 1.5 mm, narrowly oblong, pilose. Calyx 5-lobed to near base, lobes 2–2.5 × c. 0.25 mm, slightly unequal in length with one shorter than the other four, ciliate. Corolla 10–12 mm long, violet, glabrous; 2-lipped, tube c. 6 mm long, upper lip c. 5 mm long, ovate, obtuse, entire; lower lip c. 6 mm long, 3-lobed, lobes c. 1.5 × 1 mm, ovate, rounded. Filaments glabrous, c. 3 mm long, anthers included; thecae ellipsoid, c. 0.75 × 0.5 mm, glabrous, lacking basal appendages. Style 10 mm long, glabrous; ovary puberulent, rostrate. Capsule 5–6 × c. 2 mm, 4-seeded, pubescent. Seeds suborbicular, c. 1.5 × 1.5 mm. rugose.

Flowering & fruiting: Found in flower in December, June and July, and in fruit in December and June.

Habitat: “Bosque alto.” Wet tropical forest, on rocks.

Distribution: Endemic to Peru. Only recently collected in San Martin ( Fig. 4 ).

Etymology: The epithet impar (unequal) refers to the very unequal leaves characteristic of this species.

Specimens examined: PERU, Huánaco, Cassapi , Mathews 1598 (K). San Martin, Tarapoto , km 12– 14 Carretera de Tarapoto a Yurimaguas, S 6°29’, W 76°22’, 2250 ft, 03.12.1979, M. Rimachi 4760 ( US); Ibid. 09.07.1970, S. McDaniel 13814 ( US) .

Conservation status: This species is only known from four collections, two of them from the same place, one without exact geographical information and the most recent made about 45 years ago. We have no idea of the size of the original populations nor of what threats they face. The somewhat disjunct distribution suggests it may be very scattered in distribution so unlikely to be vulnerable to a single catastrophic event. Although it is more likely to have been overlooked than to have become extinct, it is clearly rare. Data Deficient ( DD).

Note s: Mathews 1598 was identified as Leptostachya heterophylla var. acutior Nees in Nees von Esenbeck (1847b: 377). It is not a type, as it was not cited in the earlier publication by Nees von Esenbeck (1847a: 150), where the variety was first described.

The Justicia trichotoma (Kuntze) Leonard complex

This consists of three strongly anisophyllous species: Justicia trichotoma , J. magdalenensis and J. maynasana , which are described below. These three species are similar in facies and might even be considered as subspecies of a single species, but their distribution is very disjunct ( Fig. 10 ), and without extensive molecular studies it seems wisest to maintain them as separate species. They can be separated by the following key:

1. Inflorescence of simple axillary spikes (Amazonian Peru)................................. J. maynasana

1. Inflorescence of trichotomously branched (apparently never simple) spikes ............................ 2

2. Calyx lobes 5.5–8 mm long ( Costa Rica and Panama).................................................... J. trichotoma

2. Calyx lobes 11–13 mm long (Magdalena valley, Colombia).......................................... J. magdalenensis

Justicia trichotoma appears to be quite common in Costa Rica ( McDade, 2020) and Panama (fide Tropicos), whereas J. magdalenensis is restricted to the Medio Magdalena region of Colombia ( Fig. 10 ). The following is a new species:

Figures

Fig. 9. Justicia impar J.R.I.Wood & P.Gallego: a. Habit; b. Leaf; c. Detail of abaxial surface of leaf; d. Bract; e. Bracteole; f. Calyx; g. Corolla opened out to show androecium; h. Anthers;j. Valve of capsule; k. Seed (a–g from Rimachi 4760;j-k from Schunke 3215; drawn by Margaret Tebbs).

Fig. 4. Distributionof selected anisophyllous species ofJusticia L.inPeru:J.impar J.R.I.Wood& P.Gallego(greensquares);J.imparifolia J.R.I.Wood & P.Gallego (red circles); J. microcalyx J.R.I.Wood & P.Gallego (pale brown triangle); J. obliqua J.R.I.Wood & P.Gallego (violet diamonds). Map prepared using QGIS v.3.28.2 (QGIS Development Team, 2023).

Fig. 10. Distribution of three related anisophyllous species of Justicia L.: J. trichotoma (Kuntze) Leonard (green circles) in Costa Rica and Panama; J. magdalenensis J.R.I.Wood (violet diamonds) in Colombia;J. maynasana J.R.I.Wood & P.Gallego (red triangle) in Peru.Map prepared using QGIS v.3.28.2 (QGIS Development Team,2023).