Khoonmengia honbaensis N.H.Xia, Y.H.Tong & X.R.Zheng, 2020

Tong, Yi-Hua, Zheng, Xi-Rong, Zhang, You Yuan, Qin, Qiao-Mei, Ni, Jing-Bo, Vu, Tien Chinh & Xia, Nian-He, 2020, Khoonmengia honbaensis, a new genus and species of temperate bamboo (Poaceae, Bambusoideae) from central-southern Vietnam, PhytoKeys 138, pp. 163-177 : 163

Khoonmengia honbaensis N.H.Xia, Y.H.Tong & X.R.Zheng sp. nov.

Type.

Vietnam, Khanh Hoa, Hon Ba Nature Reserve, 1500 m, 17 October 2017, N. H. Xia et al. BVN2017048 (holotype, IBSC!; isotypes, SING!, VNM!).

Description.

Culms erect at lower part, distally scrambling, 2-4(-10) m long; internodes terete, 20-32 cm long, 4-6 mm in diam., initially light purple, becoming gray-green, with dense brownish green dots turning black when dry; nodes conspicuous, swollen at one side, lower margin ciliate, supranodal ridge inconspicuous, intranodes glabrous. Buds elliptic, wholly sunken into culm. Branches extravaginal, often solitary at lower part of culm, and usually with one central dominant branch elongating to reiterate the culm and 1-4 lateral slender ones in the middle part of culm, lateral branches 10-25 cm long. Culm sheaths persistent, leathery, glossy, initially light purple, 8-9.5 cm long, abaxially with distinct veins, basally swollen, with a distinctive zone of transverse wrinkles; auricles and oral setae absent; blade reflexed, lanceolate, 6-9 cm long, glabrous, deciduous; ligule convex, ca. 2 mm high, glabrous. Leaves 3-8 per ultimate branch; leaf sheaths glabrous; auricles and oral setae absent; ligules convex, ca. 2 mm high; blades elliptic-lanceolate, 10-20 × 1-2.5 cm, glabrous both sides except margin ciliate at the base when young, secondary veins 3-5 pairs, transverse veins distinct. Synflorescence semelauctant, composed of only one spikelet subtended by one or several sheath-like bracts, single or several to many synflorescences arranged into a raceme or panicle which is terminal on leafy branches; spikelets 4-7 cm long, florets 8-9. Glumes (0-)1-2, ovate, ca. 10 × 3 mm, apex acute, glabrous, 11-veined. Rachilla segments flat, ca. 6 mm, glabrous, apex inflated. Lemma ovate-lanceolate, 12-13 × 5 mm, glabrous, 13-veined, apex acute with a mucro; palea slightly shorter than lemma, 11-12 × 2-3 mm, 2-keeled, keels ciliolate, apex with excurrent keel vein, 3-veined between keels and 2-veined outside keels, veins inconspicuous; lodicules 3, ovate, membranous, 3-5 × 1.5-2 mm, ciliolate, apex acuminate; stamens 3, filaments white, free, anthers tinged purplish when young, then becoming purple, ca. 7 mm long; ovary ovoid, 1 mm long, glabrous; styles 2, free, ca. 1 mm long, stigmas plumose, ca. 3 mm long. Caryopsis nut-like, with a hardened pericarp and loosely adherent lemma and palea, dark brown, fusiform, 8-9 × ca. 3 mm, apex with 2 persistent style bases.

Etymology.

Khoonmengia is named in honor of Dr. Khoon Meng Wong, a renowned botanist who has studied the bamboos and other plant groups of Southeast Asia for more than 35 years. The specific epithet is named after Hon Ba Nature Reserve, the type locality of this species.

Distribution and habitat.

This species was only found in the type locality, i.e. Hon Ba Nature Reserve, Khanh Hoa Province of Vietnam. It occurs in high mountain broadleaved forests at an elevation of ca. 1500 m.

Additional specimen examined

(paratype): VIETNAM, Khanh Hoa, Hon Ba Nature Reserve, 12°06'39.2"N, 108°56'47.2"E, C. Y. Lee et al. HIKK370 (HN!).