Temochloa elegans N. H. Xia, Y. Y. Zhang, Z. Y. Cai & Y. H. Tong, 2024

Cai, Zhuo-Yu, Zhang, You-Yuan, Tong, Yi-Hua, Vu, Tien Chinh & Xia, Nian-He, 2024, Temochloa (Poaceae, Bambusoideae), a newly-recorded bamboo genus for China and Vietnam, with new taxa and a re-interpretation of flowering structures, PhytoKeys 246, pp. 229-236 : 229-236

Temochloa elegans N. H. Xia, Y. Y. Zhang, Z. Y. Cai & Y. H. Tong sp. nov.

Figs 1 , 2

Diagnosis.

The new species resembles Temochloa liliana , but differs by its subsolid (vs. hollow) culm internodes, hairy (vs. glabrous) prophylls of the pseudospikelets, paleae longer than (vs. as long as) lemmas and acute to slightly obtuse (vs. 2 - lobed) palea apices.

Type.

China, Guangxi, Jingxi, near Bandan Village , limestone, 22 ° 53 ' 23 " N, 106 ° 21 ' 16 " E, 703 m elev., fl. (floret, flower), fr. (fructus, fruit), 10 June 2020, N. H. Xia et al. BH 85 (holotype: IBSC!) .

Description.

Clumps unicaespitose, open, spreading. Rhizomes short-necked, pachymorph. Culms scrambling; internodes subsolid, 15–30 (– 35) cm long, 4–5 mm diam., glabrous; supranodal ridges slightly prominent; sheath scar prominent with a persistent sheath-base collar. Primary branch bud solitary, nearly circular, compressed, 7–8 mm long, puberulent, the lateral edges ciliolate. Culm leaf sheath deciduous, narrowly triangular, green when young, margins glabrous, abaxial surface glabrous and white pubescent at the base, with shallow longitudinal grooves, grooves with white pubescence becoming glabrous; ligule inconspicuous; auricles and oral setae absent; culm leaf blade persistent, erect, acicular. Branches intravaginal, many and subequal at each node, central branch sometimes dominant, reiterating and approaching the size of the culm. Foliage leaves 6–13 per ultimate branch; foliage leaf sheath pubescent, margins glabrous; ligule truncate, no longer than 0.5 mm high, puberulent, ciliolate; auricles and oral setae absent; foliage leaf blades papery, lanceolate to oblong, 5–8 cm long, 0.4–0.8 cm wide, abaxial surface glabrous, adaxial surface (sub) glabrous, one margin entire, the other serrulate, base rounded-obtuse to rounded-truncate, apex acicular, acuminate, secondary longitudinal veins 2–3 pairs, transverse veins inconspicuous.

Pseudospikelets solitary, secondary pseudospikelets rarely produced, slightly compressed, prophyll oblong, 3–3.5 mm long, papery, 2 - keeled, keels ciliate, puberulent between keels, adaxial surface apically puberulent, apex acute; bracts 4–5, papery to leathery, gemmiferous or not, triangular to lanceolate, 2.5–5 mm long, abaxial surface glabrous or puberulent above the middle, adaxial surfaces glabrous or apically puberulent, 7–9 - veined, apex acute and mucronate; fertile florets 2–4, uppermost floret not fully developed; rachilla segments compressed, 4–5 mm long, glabrous; glumes absent; lemma leathery, lanceolate, ca. 6–8 mm long, both surfaces glabrous or adaxial surface apically puberulent, 9–11 - veined, apex acute and mucronate, callus inconspicuous, no more than 0.5 mm long, glabrous; palea longer than lemma, ca. 7–9 mm long, glabrous, 2 - keeled, 2–3 - veined between keels, each side 3–4 - veined, apex acute to slightly obtuse; lodicules 3, the anterior two, broadly ovate, ca. 2 mm long, 3–4 - veined, the posterior one, lanceolate, ca. 2 mm long, 1–3 - veined; stamens 6, filaments free, anthers yellow, ca. 3.5–4.5 mm long, apex emarginate; stigmas 3, 2–2.5 mm long, plumose, ovary ellipsoid, ca. 1.5 mm long. Caryopsis ellipsoid, ca. 7–8 mm long.

Phenology.

New shoots around May.

Etymology.

The specific epithet refers to its elegant habit.

Chinese name.

雅竹 (yǎ zhú).

Distribution and habitat.

This species occurs in the limestone area of southwest Guangxi, China and northeast Vietnam, at elevations of 210 (– 700) m.

Conservation status.

Up to now, T. elegans is known from only two locations in China and Vietnam. It is not very common at those locations so the number of mature clumps appears to be limited. The Vietnamese population is well protected in the Nature Reserve, while the Chinese population is distributed along the highway and not in any protected area. It should probably be categorised as Near Threatened ( NT) ( IUCN Standards and Petitions Committee 2022).

Additional specimens examined

(paratypes). Vietnam, Bac Kan, Ba Be Lake , limestone, 22 ° 25 ' 15 " N, 105 ° 36 ' 53 " E, 170 m elev., 20 May 2018, N. H. Xia et al. 2018 VNB 018 ( IBSC!, VNMN!) .

Figures

Figure 1. Floral morphology of Temochloa elegans A pseudospikelets of Neomicrocalamus sp. showing the secondary pseudospikelet (left) developed from the base of the primary pseudospikelet (right) B rachilla segment C prophyll (abaxial view) D bracts (abaxial view) E lemma (abaxial view) F palea (left: back view; right: side view) G lodicules H pistil I young fruit subtended by a palea J mature fruit K apical not fully developed floret L anther apices (left from Temochloa elegans; right from Neomicrocalamus sp. included for comparison) M anthers.

Figure 2. Morphology of Temochloa elegans A habit B foliage leaves C branch complement without a dominant central branch D branch complement with a developing dominant central branch E primary branch bud F culm internode section G culm leaf (upper half) H culm leaf (lower half) I flowering branches J spikelet proper.