Cyrtandromoea sudhansui Chowlu, A.Shenoy & Nuraliev

Chowlu, Krishna, Shenoy, Akshath & Nuraliev, Maxim S., 2024, Cyrtandromoea sudhansui (Phrymaceae), a new species from Northeast India, Phytotaxa 642 (1), pp. 104-110 : 105-108

Cyrtandromoea sudhansui Chowlu, A.Shenoy & Nuraliev , sp. nov. ( Fig. 1 & 2 )

Diagnosis:— Cyrtandromoea sudhansui differs from all the other species of the genus by the following combination of characters: mature stem with with prominent corky wings, calyx ca. 1.5 cm long, corolla 3.5–4.2 cm long, blue-purple with whitish abaxial ridges, inner surface of corolla tube bearing clavate hairs, and hairy stamens, ovary and style.

Type: — INDIA. Arunachal Pradesh: West Kameng district, Munna Camp , from Dirang to Phadam village , 27°19´37.79´´N, 92°21´1.96´´E, 1590 m a.s.l., 10 October 2023, Krishna Chowlu 41390 (holotype CAL: CAL0000253820 !, isotype ARUN!).

Description:—Herb perennial, branched, up to 0.5–2 m tall. Stem erect, with semi-woody base, quadrangular in cross section, hairy when young and glabrous when mature; mature portions of stem with prominent corky wings 1–2 mm wide; nodes with interpetiolar stipule-like thickenings. Leaves cauline, opposite, simple, petiolate. Petiole 1–2 cm long, puberulent. Blade ovate to elliptic-ovate, 12–20 × 3.5–7.5 cm, adaxially pilose, abaxially densely pubescent, apex acute, base cuneate, margin dentate to serrate, venation suprabasal-acrodromous with 6–10 secondary veins on each side of midvein, veins slightly impressed adaxally and prominently raised abaxially. Base of each lateral shoot bearing leaves much smallar than described above. Inflorescence axillary on distal (leafy) portion of shoot, 1–2- flowered cyme; peduncle densely puberulent, 2 cm long; bracts linear-lanceolate, 0.3–0.5 × 0.1 cm, puberulent on each side and along margin. Calyx actinomorphic, campanulate, green; tube appressed to corolla, 1.2 cm long, 5-angled, distinctly ridged; lobes 5, slightly diverging, broadly triangular, with ridges continuing into caudate-attenuate apices, 2 mm long and ca. 3 mm wide; calyx outside hairy on ridges and glabrous otherwise, inside minutely hairy, with some short hairs along apical margin; fruiting calyx (when immature) pale green to reddish, with tube elongating to 1.2–1.4 cm and becoming broadly ellipsoid. Corolla zygomorphic, bilabiate, 3.5–4.2 cm long, 1.8–2.2 cm wide; tube narrowly infundibuliform, inside with two prominently raised longitudinal ridges on abaxial (lower) side gradually widened towards median lobe of lower lip, 32–34 mm long, outside densely pubescent with white hairs, inside with dark purple clavate hairs on ridges and white clavate hairs otherwise (clavate hairs 0.4–0.8 mm long); upper (adaxial) lip 2-lobed and lower (abaxial) lip 3-lobed; lobes slightly overlapping at base, subequal, orbicular-obovate with retuse apices, outside (abaxially) pubescent with white hairs, inside (adaxially) sparsely hairy; median lobe of lower lip 0.6–1 cm long and 0.6–0.8 cm wide, other 4 lobes each 0.4–0.6 cm long and 0.6–0.8 cm wide; corolla blue-purple outside and inside, inside whitish towards base and with whitish ridges, with dark purple veins. Stamens 4, didynamous, appressed to adaxial side of corolla, attached near base of corolla tube; filaments slightly arcuate, ca. 1.5 cm long in posterior (adaxial) stamens and ca. 2 cm long in anterior (abaxial) stamens, white, puberulent; anthers deeply included in corolla tube, glabrous, with thecae divergent at ca. 180°, longitudinally deniscent. Disk at ovary base inconspicuous, annular, ca. 0.5 mm high, pale yellow. Ovary superior, cylindrical, ca. 0.5 cm long and 0.2 cm wide, light green, with spreading hairs; style filiform, 1.5–2 cm long, white, pubescent; stigma deeply included in corolla tube, dorsoventrally bilamellate, ca. 0.3 cm long, white. Mature fruits unknown.

Etymology: —The species is named after Dr. Sudhansu Sekhar Dash, Scientist and Technical Head, Botanical Survey of India, who has immensely worked on floristic diversity and ecology in the Eastern Himalayas.

Distribution and habitat: Cyrtandromoea sudhansui occurs on the southern slops of hills, in evergreen broadleaved forests, at an elevation of ca. 1590 m a.s.l.

Phenology: —Flowering in September–October.

Conservation status and preliminary IUCN assessment: —As this species is known only from the type locality, we categorise it as Data Deficient (DD) following the IUCN guidelines ( IUCN Standards and Petitions Subcommittee 2017).

Taxonomic notes: —We assign the new species to Cyrtandromoea , because it closely meets the descriptions of the genus provided by Burtt (1965), Yamazaki (1990), Hong et al. (1998) and Kiew & Chung (2021), as well as the generic keys by Yamazaki (1990) and Hong et al. (1998).

Cyrtandromoea sudhansui appears to be unique within Cyrtandromoea in having blue corolla, whereas in all the other species of the genus with this character documented corolla is white (rarely to pale violet or pinkish) and often with yellow anterior ridges ( Clarke 1883, Backer & Bakhuizen van den Brink 1965, Burtt 1965, Balakrishnan 1976, Yamazaki 1990, Tao et al. 1995, Hong et al. 1998, Ma et al. 2019, Kiew & Chung 2021, Bui et al. 2023). Corolla, or at least its coloration, is unknown in C. angustifolia ( Miquel 1856: 734) C.B. Clarke (1883: 187) , C. dispar C.B. Clarke (1883: 187) , C. miqueliana C.B. Clarke (1883: 187) , C. subintegra C.B. Clarke (1883: 187) and C. sumatrana Ridley (1917: 68) , all endemic to Sumatra. Additionally, the new species is readily distinguishable from the other species of Cyrtandromoea in the following combination of morphological traits: winged stem, calyx ca. 1.5 cm long and hairy along ridges, hairy stamens, hairy ovary and style.

Cyrtandromoea sudhansui is remarkably similar to C. pterocaulis in its prominently winged stem, but otherwise differs considerably from the latter species. The key provided by Burtt (1965) contains all the species of Cyrtandromoea known prior to our study except for C. pterocaulis (with “ Cyrtandromoea sp. ” corresponding to C. nicobarica ). Within Burtt’s key, C. sudhansui seems to be most close to C. subsessilis ( Miquel 1856: 733) B.L. Burtt (1965: 86) . The new species differs, however, from C. subsessilis in a set of characters outlined in Table 1 .

Figures

FIGURE 1. Cyrtandromoea sudhansui. A, B. Branches with flowers. C. Plant with immature fruits, showing adaxial surfaces of leaves. D. Portion of shoot, showing winged stem. E. Flower, front view. Photos by K. Chowlu.

FIGURE 2. Cyrtandromoea sudhansui. A. Shoot with anthetic and post-anthetic flowers. B, C. Leaf, adaxial and abaxial surfaces. D. Flower, front-adaxial view. E. Flower, side view. F. Flower, front view. G. Bracts. H, I. Artificially opened calyx, views from outside and from inside. J. Corolla artificially opened along adaxial side, view from inside. K. Androecium. L. Gynoecium and disk. Photos by K. Chowlu.