Alpinia hongiaoensis Tagane

Alpinia hongiaoensis Tagane, sp. nov. —Fig. 14. 

Fig. 14. Alpinia hongiaoensis Tagane. A: Habit. B: Ligule. C: Portion of lower leaf surface. D: Inflorescence with flower buds. E: Front view of flower. F: Side view of flower. All photographs from Yahara et al. V9886 taken on 22 April 2019; all tak- en by Shuichiro Tagane. 

Alpinia hongiaoensis is similar to A. newmanii N. S. Lý from Quang Nai Province, southern Vietnam (Lý 2017), in having an erect, racemose inflorescence, absence of bracts and presence of bracteoles and yellow labellum tinged with red in the center, but differs in size, to 70 cm tall (vs. 1.7 m in A. newmanii), smaller dark green lamina (26– 27.5 × 4.2–4.8 cm vs. glaucous green lamina adaxially, 34.7–35.5 × 3.8–4.9 cm) and 1 epigynous gland (vs. 2). 

Typus. 

VieTnam. Lam Dong Province. Bidoup-Nui Ba National Park: Hon Giao, in wet evergreen forest, 1,637 m, 12°11′09.23′′N, 108°42′55.46′′E, 22 Apr. 2019, T. Yahara, S. Tagane, A. Nagahama, N. Komada, H.V. Thanh V9886 [fl.] (holo- KYO, iso- DLU, KAG). 

Herbs, perennial, 70 cm tall. Rhizome creeping, distance between neighboring leaf shoots 3.5–4 cm, 4 mm in diam., reddish brown or yellowish brown, sparsely hairy; rhizome scales broadly ovate-triangular, 3–4 mm long, glabrous on both surfaces. Leafy shoots of mature flowering indi- viduals with 9–11 leaves, basal bladeless sheaths 2, 9.2–21.6 cm, longitudinally striate, yellowish brown or dark reddish brown, densely minutely pubescent outside, glabrous inside; leaf-bearing sheaths 7–9, longitudinally striate, dull yellowish brown or pale brown; upper leaf sheath tinged light purplish red, densely minutely pubescent outside, glabrous inside; ligules 0.7–1.1 cm long, apex rounded, indumentum same as leaf sheath except villous near margin; petiole 0.8–1.6 cm long, minutely hairy, concave adaxially, rounded abaxially; lamina oblong-elliptic, 12–18.7 × 3.6– 3.8 cm (smallest uppermost leaves), 26–27.5 × 4.2–4.8 cm (largest leaves), chartaceous, minute- ly pubescent on both surfaces, deep green adaxi- ally, pale green abaxially, apex long-acuminate to caudate, acumen to 1.4 cm long, densely ap- pressed hairy, base acute to cuneate, margin densely ciliate. Inflorescence a terminal raceme, erect, to 11 cm long, 12-flowered; peduncle 5.5–7 cm long, ca. 2 mm in diam., dark red in vivo, red- dish brown in sicco, villous; sheathing bracts of inflorescence ca. 8 cm long, caducous; rachis 6.5 cm long, villous. Floral bracts absent. Bracteoles tubular, ca. 2 cm long, 0.8–1 cm in diam., (ovate, 2.4 cm wide when opened and flattened), pubes- cent outside, glabrous inside, apical margin densely ciliate. Flowers ca. 5 cm long. Pedicels 2–4 mm long, pubescent. Calyx campanulate, 1.8 cm long, 0.9 cm in diam. at widest point (oblong- obovate, ca. 2 cm wide when opened and flat- tened), unequally 3-lobed at apex, lobes oblong- ovate, 0.3–0.5 cm long, pubescent outside, gla- brous inside, margin densely ciliate, apex mucro- nate, mucro 0.1–0.2 mm long. Floral tube ca. 1.5 cm long, widening gradually toward apex, sparse- ly hairy outside, glabrous inside. Dorsal corolla lobe oblong, 2.3 × 1.7 cm, concave, white, sparse- ly hairy outside, glabrous inside, margin ciliate, apex cucullate. Lateral corolla lobes 2, oblong- elliptic, 2.7 × 1.1–1.2 cm, sparsely hairy outside, glabrous inside, margin ciliate, apex slightly cu- cullate. Labellum broadly ovate, concave at base, flattened in upper half, ca. 3 × 2.1 cm when flat- tened, light yellow with orangish red center in vivo, glabrous, margin slightly deflexed near apex, apex bilobed, lobes ca. 2.5 mm long, apex obtuse. Lateral staminodes asymmetric, triangu- lar, ca. 4 × 1 mm, with a few hairs along margin. Stamens attached to floral tube at angle of ca. 180 degree, curved inward, filament ca. 1 cm long, sparsely hairy, anther 1.3 cm long, short hairy, thecae as long as anther, ca. 1.1 mm wide, gla- brous; anther crests absent. Style ca. 4.2 cm long, stigma funnel-shaped, ca. 1 mm in diam., hairy. Epigynous gland 1, horseshoe shaped, ca. 2.5 mm long, glabrous. Ovary ellipsoid, 3.5 × 2.5 mm, villous, 3-locular, ovules 7–8 per locule; placen- tation axile. Fruits and seeds not seen. 

Distribution. 

Vietnam (known only from the Hon Giao area in Bidoup-Nui Ba National Park). 

Phenology. 

Flowering specimens were col- lected in April. 

Note. 

Alpinia hongiaoensis belongs to sub- sect. Catimbium (Horan.) R. M. Smith, which comprises about 34 species. The members are characterized by unbranched inflorescences, bracts absent, bracteoles nearly enclosing the flower buds, calyx split unilaterally, showy labellum usually over 3 cm long and yellowish orange marked with crimson red, staminodes subulate, and anther ecristate (Smith 1990). In Vietnam, 12 species of subsect. Catimbium have been report- ed (Lý 2017); A. hongiaoensis is the 13th. 

Soure: Shuichiro Tagane, Nguyen Van Ngoc, Hoang Thi Binh, Ai Nagahama, Meng Zhang, Truong Quang Cuong, Le Van Son, Van-Son Dang, Hironori Toyama, Natsuki Komada, Hidetoshi Nagamasu, Tetsukazu Yahara; Fifteen New Species of Angiosperms from Bidoup-Nui BaNational Park, Southern Highlands of Vietnam; Acta Phytotaxonomica et Geobotanica; Volume 71 (2020) Issue 3