Gigantochloa brachystachya Q. M. Qin, Y. Zeng & N. H. Xia, 2023

Qin, Qiao-Mei, Tong, Yi-Hua, Zeng, Yi, Cai, Zhuo-Yu, Ni, Jing-Bo & Xia, Nian-He, 2023, Two new species of Gigantochloa (Poaceae: Bambusoideae) from Yunnan, China, Phytotaxa 616 (1), pp. 79-88 : 80-83

publication ID	https://doi.org/ 10.11646/phytotaxa.616.1.6
DOI	https://doi.org/10.5281/zenodo.8404138
persistent identifier	https://treatment.plazi.org/id/03DDAC67-E717-DB46-FF0C-FB92FC6DFF36
treatment provided by	Plazi
scientific name	Gigantochloa brachystachya Q. M. Qin, Y. Zeng & N. H. Xia
status	sp. nov.

Treatment

Gigantochloa brachystachya Q. M. Qin, Y. Zeng & N. H. Xia View in CoL , sp. nov., Figs. 1–2 View FIGURE 1 View FIGURE 2

Type: — CHNIA. Yunnan: Jinghong City, Damenglong, Manjingkang , elev. 662 m, 5 September 2012, Yi Zeng 26 (holotype IBSC!).

Diagnosis:— Gigantochloa brachystachya is similar to G. levis (Blanco 1837: 272) Merrill (1916: 61) , but differs in the infranodal region with a ring of white (vs. brown) hairs, culm leaf blade erect (vs. reflexed), auricle smaller (ca. 1 cm × 1 mm vs. ca. 2 cm × 7 mm) and linear (vs. oblong), ligule 5–10 mm (vs. 3–6 mm) tall, leaf sheath glabrous (vs. white-hispid), ligule 3–5 mm (vs. ca. 1 mm) tall, and outer ligule ca. 2–2.5 mm (vs. ca. 0.5 mm) tall ( Table 1 View TABLE 1 ).

Description: —Rhizomes pachymorph. Culms erect, 12–15 m tall, 3–7 cm in diam., walls ca. 1 cm thick, lower nodes with a few verticillate aerial roots; internodes 32–42 cm long, terete, greyish-green, white pubescent; node slightly prominent, intranode ca. 1 cm tall, with a ring of pale brown hairs, infranodal region with a ring of white hairs. Branches 0.5–1.0 m long, developing from the 7 th –14 th node above the ground, numerous, dominant branch inconspicuous. Culm leaf sheath deciduous, leathery, densely black setose abaxially, 1/2 as long as internodes; blades erect, lanceolate, 1/4 as long as culm leaf sheaths; auricles linear, ca. 1 cm wide and ca. 1 mm tall, margin with oral setae; ligule 5–10 mm tall, dentate. Foliage leaves 8–11 per ultimate branch; sheath glabrous, margin ciliate; auricles absent; ligule 3–5 mm tall, dentate; outer ligule 2.0– 2.5 mm tall; petiole 3–5 mm long; blades lanceolate, 33–41× 3.0– 4.2 cm, glabrous, secondary veins 10–12 pairs. Inflorescence iterauctant; pseudospikelets densely clustered at nodes of flowering branches, 9–11 mm long, 2.9–3.4 mm wide, with (1–) 2 or 3 glumes, 3 perfect florets and a terminal sterile floret consisting of only an empty lemma ca. 8 mm long; rachilla very short; lemma 7.5–11.0 mm long, abaxially glabrous, with a short terminal mucro and short-hairy fringes; palea 6.5–8.0 mm long, 0.8–2.0 mm wide, keels 2, keels and margins ciliate, 3 or 4 veins between keels, and 1 or 2 outside each keel; lodicules absent or rarely 1; stamens 6, filaments united into a tube, translucent; anthers yellow, 5–6 mm long, with an apical hairy mucro ca. 0.3 mm long; ovary subcylindrical with a slightly expanded, thickened and hairy apex, ca. 1.4 mm long; style terminating in a single hairy stigma, 1.0– 1.2 cm long. Caryopsis ca. 1 cm long.

Distribution and Habitat: — Gigantochloa brachystachya is endemic to Yunnan, China. It was cultivated near villages at an elevation of about 600 m.

Phenology: New shoots August to September, flowering September.

Etymology: —The specific epithet is derived from its short and small spikelets.

Additional specimens examined (paratypes): — CHINA. Yunnan: Mengla, Xishuangbanna Tropical Botanical Garden , 21°55’N, 101°15’E, elev. 548 m, 31 August 2012, Yi Zeng 18 ( IBSC); GoogleMaps Yi Zeng 17 (IBSC, only the culm leaf sheath) GoogleMaps ; ibid., elev. 540–550 m, 19 October 2016, Qiao-Mei Qin 140, 141, 142 ( IBSC) GoogleMaps .

Chinese vernacular names:—ḂDzfflfi (pinyin: duǎn suì jù zhú).