Justicia pusilla M.J. Silva, 2021

Silva, Marcos José Da, 2021, A new and endangered species of Justicia L. (Justicieae-Acanthaceae) from the riparian forests of northern Goiás State, Brazil, Phytotaxa 525 (1), pp. 37-45 : 38-43

Justicia pusilla M.J. Silva , sp. nov.

Type:— BRAZIL. Goiás: Goiás: Niquelândia, Reserva particular de Desenvolvimento Sustentável Legado Verdes do Cerrado, Núcleo Engenho, Córrego da Sociedade , ca. 150 m a partir do Corrégo, mata ciliar, crescendo em barranco e sobre rochas em ambiente sombreado, 14°38’35”S 48°28’34”W, 629 m elev., 23 June 2021, fl., fr., M. J. Silva & I. S. Santos 12685 (holotype UFG!; isotypes: UB!, RB!, CEN!)

Diagnosis: —This new species is most similar to J. laevilingui s Ness (1847: 120), but differs by having an erect habit (vs. procumbent or decumbent), leaves indumented on both surfaces (vs. glabrous), spikes always simple (vs. simples or paniculiform), fertile bracts indumented and ciliate (vs. glabrous and non-ciliate), bracteoles ciliate (vs. nonciliate), calyx lobes 3–4 mm long, indumented externally (vs. 7–8 mm long, glabrous), corolla 5–5.1 mm long, white with a lilac spot on the palate, or uniformly white, shortly pubescent internally in the central region (vs. 11–18 mm long, lilac, with a white spot on the palate, glabrous internally), and seeds suborbicular and hispidulous (vs. cordiform, glabrous).

Description —Herbs or subshrubs 5–28 cm tall; stems erect, cylindrical, non-dilated or constricted above the nodes, uniformly tomentose and shortly hispid, trichomes hyaline. Leaves slightly anisophyllous, petiolate; petiole 0.2–0.5 cm long, shortly tomentose, slightly sulcate above; blades 2.6–7.5 × 0.5–1.3 cm, elliptic, narrowly elliptic, elliptic-obovate, spatulate, or sometimes lanceolate, pubescent on both surfaces, especially on the veins on the abaxial surface, base attenuated or slightly asymmetrical, margin entire or more rarely irregularly crenate near the apex, sparsely ciliate, apex acute, acuminate or obtuse, cystoliths inconspicuous, dark green adaxially, opaque green abaxially, midrib prominent abaxially, secondary veins 5–7 pairs, the tertiary veins impressed on both surfaces. Spikes simple, terminal, lax and congested; peduncles (2) 3–4 cm long, rachis (2.2) 4.5–6 cm long, both shortly tomentose; sterile bracts 4.5–4.8 × 0.6–0.7 mm, sessile, elliptic, oblanceolate, base attenuated, apex acuminate, ciliate, sparsely shortly hirsute on both surfaces, trichomes eglandular; bracteoles 3.5–6 × 0.2–0.25 mm, sessile, linear, apex acute, glabrous on both surfaces, ciliate; calyxes green, 5-lobed; lobes equal, 3.8–4 × ca. 0.2 mm, linear, glabrous internally and pubescent externally, trichomes eglandular, margins sparsely ciliate. Corolla bilabiate, tube and lips white or lips white, with a lilac spot on the palate, 5–5.1 mm long, tube ca. 1.1 mm long at base, central region 1.9–2 mm long, pubescent above the stamens and near the lobes, upper lip 2.3–2.4 × 1.27–1.4 mm, entire, lower lip ca. 2.3 mm long, 3-lobed, lobes oblong or obtuse, central lobe 2–2.1 × 1.2 mm, lateral lobes 1.1–1.2 × 0.9–1.2 mm; stamens 2, filaments white, attached near the upper portion of corolla tube, free portion of the filaments 2–2.1 mm long, pubescent at base, connectives not elongated, thecae whitish, superposed, upper thecae ca. 0.5 mm long, lower portion 0.3 mm long, both without appendages; connectives narrow; ovary oblong ca. 1 × 0.3 mm, glabrous, style ca. 4 mm long, stigma obtuse. Capsule ca. 4 × 1.2 mm, clavate, light green, puberulous with eglandular trichomes. Seeds 4, ca. 0.7 × 0.7 mm, suborbicular, compressed, not cordate, surface smooth, hispidulous, base slightly asymmetric, brownish.

Additional specimens examined (paratypes): — BRAZIL. Goiás: Niquelândia, Reserva Particular de Desenvolvimento Sustentável Legado Verdes do Cerrado, Núcleo Engenho, Área do Córrego dos Macacos, 14°38’34”S 48°28’34”W, 656 m elev., cerca de 50 m à esquerda da Ponte do Córrego dos Macacos, 23 April 2021, fl., M. J. Silva & F.D. Santos 12371 (UFG), 12372 (UFG), 12377 (UFG); ibd., 14°38’33”S 48°28’40”W, 657 m elev., cerca de 5 m à esquerda da Ponte do Córrego dos Macacos crescendo sobre barranco, trecho sombreado, 22 April 2021, fl., M. J. Silva & F.D. Santos 12306 (UFG), 12307 (UFG), 12308 (UFG), 12309 (UFG), 12310 (UFG); ibd., mata de galeria na borda da vegetação em ambiente sobreado, ca. 15 m à erquerda da ponte, 14°39’45”S 48°27’33”W, 716 m elev., 28 May 2021, fl., M. J. Silva & F.D. Santos 12500 (UFG), 12501 (UFG); ibd., área do Córrego da Sociedade, cerca de 10 m à esquerda da ponte do Córrego, 14°38’34”S 48°28’’39”W, 667 m elev., 28 May 2021, fl., M. J. Silva & F.D. Santos 12503 (UFG), 12504 (UFG); ibd., ca. 150 m a partir do Córrego Sociedade, 14°38’35”S 48°28’34”W, 629 m elev., 23 June 2021, fl., fr., M. J. Silva 12680 (UFG), M. J. Silva 12681 (UFG), M. J. Silva 12682 (UFG), M. J. Silva 12683 (UFG), M. J. Silva 12684 (UFG), M. J. Silva 12686 (UFG), M. J. Silva 12687 (UFG), M. J. Silva 12688 (UFG), M. J. Silva 12689 (UFG), M. J. Silva 12690 (UFG); ibd., Córrego do Padre, ca. 10 m a partir da ponte do corrégo do lado esquerdo, 14°38’18”S 48°28’52”W, 657 m elev., 28 May 2021, fl., M. J. Silva & F.D. Santos 12506 (UFG), 12514 (UFG); ibd., Córrego do Padre, ca. 20 m a partir da ponte do córrego do lado esquerdo, 14°38’19”S 48°28’52”W, 650 m elev., 29 May 2021, fl., M. J. Silva & F.D. Santos 12587 (UFG), 12588 (UFG), 12589 (UFG), 12590 (UFG); Região do Traíras, cerca de 80 ma partir da trilha do Rio Traíras em barranco, 14°36’31”S, 48°28’42”W, 644 m elev., 29 May 2021, fl., M. J. Silva & F.D. Santos 12532 (UFG).

Distribution and habitat: —Species previously collected only in the Legado Verdes do Cerrado Private Sustainable Development Reserve, municipality of Niquelândia, Goiás State, Brazil, in “Córregos dos Macacos”, “Padre”, and “Sociedade”, as well as along the banks of the Traíras River. Justicia pusilla grows in ravines, on rock outcrops, in aquatic environments, in periodically flooded sites, and in shaded areas at 600– 750 m.a.s.l. It forms populations with up to 30 individuals.

Phenology: —Species collected with flowers from April to May and with flowers and fruits in May.

Etymology —The specific epithet “ pusilla ” is derived from the Latin “ pusillus ”, alluding to the small size of the species as compared to congeners.

Preliminary conservation status: — Species with an Extent of Occurrence estimated at 4.377 km 2, which is therefore classified as Critically Endangered (CR) Criteria B 1 subcriteria b(i, iv, v), and criteria D. It was collected, however, in gallery forests, a very common vegetation type in the northern part of Goiás State, and later exploratory collections may reveal new sites of occurrence.

Taxonomic notes: — Justicia pusilla is characterized by perennial herb, cystoliths not apparent, simple spike with 1 or 2 flowers per node, the axis eglandular, bracts lanceolate, larger than the calyx, calyx 5-partite, segments equal, corolla white, anther-thecae slightly superposed, parallel to oblique, or at right-angles, one slightly larger than the other, without appendages, ovary and capsules glabrous with seeds compressed. Therefore, it belongs to Justicia sect. Dianthera subsect. Dianthera ( Linnaeus 1753: 27) Graham (1988: 599) according to the classification of Graham (1988). The subsection corresponds to the Dianthera clade recognized by Kiel et al. (2018) that includes plants from aquatic or subaquatic habitats with inflorescences of axillary pedunculate spikes, 5-parted calyxes with equal segments, and discoid seeds rugose with minute papillae or ornamented with irregular, column-shaped tubercles. To occupy aquatic or subaquatic habitats, Justicia pusilla has pedunculate and always terminal spikes, calyxes with 5-parted equal segments, and discoid seeds.

Sartin (2015) recorded 26 species of Justicia in Goiás State, three of which are probably new to science but not yet published, i.e., J. horty-maitreyae Sartin & Kameyama (2015: 83) , J. indespecta Sartin & Kameyama (2015: 67) and J. neglecta Sartin & Kameyama (2015: 87) . Chagas & Costa-Lima (2020) recorded 23 species of that genus in the same state. J. pusilla resembles J. laevilingui s (Ness 1847: 120) Lindau (1894: 20), the only taxa belonging to J. sect. Dianthera subsect. Dianthera previously reported from Goiás State, in sharing a herbaceous or subshrub habit, stems neither constricted nor dilated above the nodes, bracts non-imbricate, calyx with five equal lobes, anthers with poorly developed connectives, thecae without appendages, and capsules glabrous. However, the characters listed in table 1 , serve to differentiate such species.

Among the undescribed new taxa proposed by Sartin (2015) from Goiás State, J. pusilla superficially resembles J. indespecta by having a subshrub habit, cylindrical or subcylindrical stems, petiolate leaves, peduncle spikes, bracts and bracteoles sessile, as well as small flowers, but differs from J. indespecta in several ways, such as its growth aspect, the type of indumentum on the stems and its distribution, type of inflorescence, corolla colors, features of the calyx lobes, as well as the dimensions of the leaf blade, petiole, corolla lobes, stamen filaments, bracts and bracteoles, and the vestiture of the latter. It can be easily distinguished from J. indespecta by an erect habit (vs. procumbent or erect), stems tomentose and shortly hispid, without dilatation above the nodes (vs. scabrous or pubescent, with dilatation above the nodes), leaves strigillose on both surfaces (vs. glabrous or strigose-pubescent on the petiole and near the veins), spikes simple and always terminal (vs. simple or compound, axillary and terminal), bracts 4.5–4.8 mm long, shortly hispid on both surfaces (vs. 5–7 mm long, pilose on adaxial surface and glandular-pilose on the abaxial surface), bracteoles 3.5–6 × 0.2–0.25 mm (vs. 4–6 × 0.2–0.3 mm), calyx 5 partite, the lobes equal or slightly subequal (vs. 5 partite, lobes unequal in 2+2+1 pattern), corolla 5–5.1 mm long, white with a lilac spot on the palate (vs. Ca. 6 mm, lilac with a white spot on the palate), as well as capsules 4–4.1 × 1.2–1.3 mm long, clavate and puberulous (vs. ca. 6– 1 mm, panduriform, glabrous).