Vietnam • Gia Lai Province: Son Lang Commune, Kon Chu Rang Nature Reserve, 14°30'46.7"N, 108°32'46.6"E, 986 m a.s.l., 19 September 2017, D.V. Hai, T.D. Binh, L.N. Han, B.H. Quang, D.H. Son KCR 317 (holotype HN!; isotypes HN!).

Similar to Staurogyne concinnula (Hance) Kuntze and S. debilis (T.Anderson) C.B.Clarke in habit (herbs about 10–20 cm tall), lax racemes, and white corolla. It is distinguished from S. concinnula by its longer bracts (5–8 vs. 2–4 mm), longer calyx (10–13 mm vs. 5–7 mm long), longer corolla (ca. 1.5–2 cm vs. ca. 1 cm long), and larger capsules (8–9 × 2.5–3 mm vs. 4–6 × 1.5 mm). The new species differs from S. debilis in having longer (3–9.5 cm vs. 2.5–4 cm) oblanceolate (vs. elliptic, oblong, or oblong-ovate) leaves, larger bracts (5–8 × 1–2 mm vs. 2 × 0.4 mm), longer calyx (10–13 mm vs. 5–6 mm long), longer corolla (ca. 1.5–2 cm vs. ca. 1 cm long), and longer capsules (8–9 × 2.5–3 mm vs. ca. 6 mm long). A detailed comparison of these three species is provided in Table 1.

Herbs to 20 cm tall, branching at the stem base or above the base. Stems stout, terete, pubescent, brown-purple. Leaves opposite; petiole 0.5–2.0 cm long, pubescent, brown-purple; blade oblanceolate, 3–9.5 × 0.7–2.0 cm, base cuneate and decurrent onto the petiole, margin slightly sinuate and revolute on the abaxial side, apex obtuse; blade adaxially dark green, glabrous, with dark green cystoliths, abaxially whitish green, sparsely pubescent along veins and glabrous otherwise; midvein flat adaxially and raised abaxially; secondary veins 6–8 on each side of the midvein, netted near the margin. Racemes terminal and axillary, lax, 6–13 cm long, 4–14-flowered; peduncle and rachis pubescent, brown-purple; bracts lanceolate to subulate, 5–8 × 1–2 mm, brown-purple, margin entire, apex acute to obtuse, adaxially glabrous, abaxially sparsely pubescent along veins, midvein flat adaxially and raised abaxially; bracteoles (2 per flower) opposite, attached to the pedicel just below the calyx, linear, 5–7 mm long, both surfaces almost glabrous. Pedicel 4–6 mm long, pubescent, purple. Flower weakly zygomorphic. Calyx 5-lobed nearly to the base, purple; lobes linear, almost glabrous but sparsely pubescent on the margin and midvein, unequal in size; unpaired (adaxial) lobe and lobes of the abaxial pair 10–13 mm long; lobes of the adaxial pair 8–11 mm long. Corolla ca. 1.5–2 cm long, outside glabrous or shortly pubescent, inside mostly glabrous but with a tuft of hairs at the level of transition between the narrow and wide portions of the tube (i.e. at the level of the stamen attachment), white and sometimes with slight purple tint; tube with a cylindrical proximal portion ca. 3 mm long and 1.0–1.5 mm in diameter, widening to a cylindrical distal portion 11–12 mm long and 3.0–3.5 mm in diameter, mostly straight but slightly bent to the adaxial side at the transitional level; lobes 5, widely spreading (corolla rotate), slightly unequal, oblong, rounded at apex, 4.0–5.0(6.0) × 2.0–3.5 mm; abaxial lobe with an apical incision ca. 0.5 mm deep. Stamens 4, didynamous, inserted at the transition between the narrow and wide portions of the corolla tube, included, white; posterior (adaxial) stamens 6–7 mm long, anterior (abaxial) stamens 7–9 mm long; filaments almost straight but bent downwards near their apices, glandular hairy; anthers with broad connectives and deeply separated thecae, appressed to the adaxial side of the corolla tube; thecae 1.0 × 0.5 mm, margin glabrous; staminode ca. 0.5 mm long, brown. Disk annular, white, smooth and lustrous. Ovary 1–2 mm long, ovoid-oblong, glabrous, green, bilocular; ovules 26–28 per locule, aligned in a row from the base to near to the apex of each locule; style appressed to the adaxial side of the corolla tube, near the base constricted by the bases of the stamen filaments, 11–14 mm long, glabrous, white; stigma unequally 2-lobed, slightly exserted; adaxial stigma lobe 0.5 mm long, apically divided into 2 small lobules, each lobule serrate around apex; abaxial stigma lobe 1.0 mm long, serrate around apex. Capsule oblong, 8–9 × 2.5–3.0 mm, glabrous, 52–56-seeded; seeds oblong to narrowly ovoid, compressed, 1.0 × 0.7 mm, alveolate.

Staurogyne konchurangensis is currently known only from Kon Chu Rang Nature Reserve in Gia Lai Province, Vietnam. It grows under the shade of primary and secondary evergreen broad-leaved forest on fertile soil, along the streams at elevations of 900–1000 m.

Flowering and fruiting from May to November.

The species is named after its type locality, Kon Chu Rang Nature Reserve.

Vietnamese (proposed here): Nhụy thập kon chư răng.

Staurogyne konchurangensis occurs in a legally protected territory, i.e. the Kon Chu Rang Nature Reserve. It grows at undisturbed sites where only a slight anthropogenic threat has been detected. There are no data on its population size and structure. Therefore, we preliminarily assess its status as ‘Data Deficient’ (DD) according to the IUCN Red List Categories and Criteria (IUCN 2024).

Vietnam • Gia Lai Province: Son Lang Commune, Kon Chu Rang Nature Reserve, 29 km ESE of Mang Den town, forest, river bank, 14°31'00"N, 108°32'30"E, 980 m a.s.l., 28 May 2016, M.S. Nuraliev 1584 (HN; MW MW0595920, MW0595921); • Gia Lai Province: Son Lang Commune, Kon Chu Rang Nature Reserve, 14°30'42.3"N, 108°34'23.2"E, 983 m a.s.l., 26 July 2017, D.V. Hai, T.D. Binh, D.T. Hoan, K.S. Nguyen, B.H. Quang, D.H. Son KCR 82 (HN); • Gia Lai Province: Son Lang Commune, Kon Chu Rang Nature Reserve, 29 km ESE of Mang Den town, forest, river bank, near waterfall, 14°30'50"N, 108°32'46"E, 1000 m a.s.l., 29 November 2022, M.S. Nuraliev, C.I. Fomichev, D.F. Lyskov NUR 3913 (MW MW0595922, MW0595923).

Staurogyne konchurangensis is readily distinguishable from all its congeners by having brown-purple pubescent stems, lanceolate to subulate brown-purple bracts, and a white corolla approximately 1.5–2 cm long. The differences of the new species from its morphologically closest relatives, S. concinnula and S. debilis, are outlined in the diagnosis.

Flowers of S. konchurangensis often appear to have inverted or oblique orientation. While this phenomenon may result from resupination, a condition known in some members of Acanthaceae (e.g. in many Strobilanthinae: Moylan et al. 2004), resupination has never been documented in Staurogyne. To find out the reasons for the non-typical flower orientation in this species, further studies are required, including examination of living material. Apart from resupination, it can possibly be a result of the inflorescence rachis and/or pedicel bending.

Vietnam • Tuyen Quang Province [previously Ha Giang Province, Quan Ba District]: Tung Vai Commune, Thang village, around point 21°03'13.4"N, 104°51'48.8"E, steep rocky slopes of streams valleys composed of eroded stratified highly eroded limestone, 1000–1200 m, primary evergreen broad-leaved very humid forests, terrestrial herb to 1.2 m tall on steep shady slopes, rare, 23 April 2018, L. Averyanov, K.S. Nguyen, N.T. Hiep, N.Q. Hieu, C.Q. Ngan, T. Maisak, VR 750 (holotype LE LE01050144!; isotype HN!).

Herbs to 1.2 m tall, usually branching. Stems stout, terete, pubescent, green. Leaves opposite; petiole 3.5–7.5 cm long, pubescent, green; blade elliptic, 12–18 × 5–8 cm, base cuneate, margin entire or slightly sinuate, apex acute; blade adaxially dark green, pubescent, abaxially pale green, densely pubescent, especially on midvein and secondary veins; secondary veins 6–9 on each side of the midvein, netted near the margin. Racemes terminal and axillary, dense, 7–9 cm long, many-flowered; peduncle and rachis pubescent, green; bracts lanceolate to ovate, 8–20 × 3–10 mm, green, margin ciliate, apex acute, adaxially puberulent, abaxially pubescent, with 2–3 pairs of secondary veins; bracteoles (2 per flower) opposite, attached to the pedicel just below the calyx, narrowly oblanceolate to linear, 12–13 × 2–3 mm, margin ciliate, apex acute, adaxially puberulent, abaxially pubescent. Pedicel 2–3 mm long, pubescent, green. Flower weakly zygomorphic. Calyx 5-lobed nearly to the base; lobes linear, adaxially puberulent, abaxially pubescent, margin ciliate, unequal in size; unpaired (adaxial) lobe and lobes of the abaxial pair 15.0–15.5 × 2 mm, lobes of the adaxial pair 14.0–14.5 × 1.0–1.5 mm. Corolla ca. 3 cm long, outside shortly pubescent, inside shortly pubescent and hirsute below stamen bases, outside bright purple except for whitish proximal portion of the tube, inside bright purple except for pale purple adaxial side (2 lobes and sector of the tube), outside and inside with ca. 20 dark longitudinal lines on the tube; tube with a cylindrical proximal portion 9 mm long and 2.0–2.5 mm in diameter, widening to a cylindrical distal portion 15–16 mm long and 5.0–5.5 mm in diameter, slightly bent to the adaxial side at the transitional level; lobes 5, slightly unequal, oblong to suborbicular, ca. 5 mm in diameter. Stamens 4, didynamous, inserted at the transition between the narrow and wide portion of the corolla tube, included, white; posterior (adaxial) stamens 11–12 mm long, anterior (abaxial) stamens 14–15 mm long; filaments almost straight but bent downwards near their apices, glandular hairy (denser so towards apex); anthers with broad connectives and deeply separated thecae; thecae ca. 2 × 1 mm, margin glandular hairy; thecae connected in pairs; staminode 3.5–4.0 mm long, glabrous, light brown. Disk annular, pale green, smooth and lustrous. Ovary 2.5–3.0 mm long, ovoid-oblong, glabrous, green, bilocular; style appressed to the adaxial side of the corolla tube, near the base constricted by the bases of the stamen filaments, 2.5–2.8 cm long, glabrous, white; stigma unequally 2-lobed, slightly exserted; adaxial stigma lobe 2.5 mm long, apex serrate; abaxial stigma lobe 3 mm long, apex serrate. Capsule oblong, 8–9 × 3 mm, glabrous, 56–60-seeded; seeds oblong to narrowly ovoid, compressed, 0.9–1.0 × 0.5 mm, alveolate, pubescent.

Staurogyne purpurea is currently known from Bat Dai Son Nature Reserve and Phong Quang Nature Reserve in Tuy­en Quang [previously Ha Giang] Province, Vietnam. It grows under the shade of very humid primary evergreen broad-leaved forests, and on steep rocky slopes of stream valleys composed of stratified, highly eroded limestone, at elevations of 800–1200 m.

Flowering in April; fruiting in June–July.

The epithet “purpurea” apparently refers to the purple corolla of this species.

Vietnamese (proposed here): Nhụy thập hồng.

Staurogyne purpurea was collected from two localities in Tuyen Quang [previously Ha Giang] Province, northern Vietnam. Both localities are within legally protected areas, namely the Bat Dai Son Nature Reserve and Phong Quang Nature Reserve. The new species grows at undisturbed sites, and no anthropogenic threat has been detected. Pop­ulation assessment in the field has never been performed. According to our prediction, there are limestone mountains with habitat conditions similar to those of the type locality in Tuyen Quang, Cao Bang, and Lang Son provinces of northern Vietnam, in which more populations of the species probably occur. Therefore, we preliminarily assess its status as ‘Data Deficient’ (DD) according to the IUCN Red List Categories and Criteria (IUCN 2024).

Vietnam • Tuyen Quang Province [previously Ha Giang Province, Quan Ba District]: Tung Vai Commune, Thang village, Bat Dai Son Nature Reserve, around point 21°03'13.4"N, 104°51'48.8"E, at elevation 1050–1150 m a.s.l., steep slopes of streams valleys composed of stratified highly eroded limestone, primary evergreen broad-leaved very humid forests, terrestrial herb to 1 m tall on shady rocky slopes, flower purple, 21 April 2018, L. Averyanov, K.S. Nguyen, N.T. Hiep, N.Q. Hieu, C.Q. Ngan, T. Maisak, VR 503 (paratypes: HN, LE LE01049245, LE01049485); • ibid., 4 April 2024, B.H. Quang, T.D. Binh BHQ 1056 (HN); • Tuyen Quang Province [previously Ha Giang Province, Vi Xuyen District]: Minh Tan Commune, Phong Quang Nature Reserve, 22°55'16.5"N, 104°53'57.0"E, elev. 773 m, 13 April 2025, B.H. Quang, N.T.T. Huong, D.T. Hoan, L.N. Han, N.T. Thuy, T.D. Binh VAST-PQ 05 (HN); • ibid., 28 June 2026, D.V. Hai, V.S. Sinh DVH 469 (HN).

Since Averyanov et al. (2020; figs 718–720) provided only a brief description of this species, the present paper offers its first comprehensive account, including detailed morphological data and analytical illustrations. Morphologically, S. purpurea is most similar to S. caobangensis D.V.Hai & Joongku Lee, endemic to northern Vietnam, and S. vicina Benoist, known from Yunnan (China) and northern Vietnam, but differs from both species by its leaf blades 12–18 cm long (vs. 9–10 cm long in S. caobangensis and 6–15 cm long in S. vicina), lanceolate to ovate bracts (vs. ovate to deltoid and linear, respectively), and narrowly oblanceolate to linear bracteoles (vs. ovate to obovate and lanceolate or linear, respectively). It is further distinguished by its bright purple corolla (vs. pure white in both allied species). A detailed comparison of these three species is provided in Table 2.