Fargesia angustissima T.P. Yi

Ye, Xia-Ying, Xu, Zu-Chang, Cheng, Yue-Hong, Wang, Wei-Hua & Li, De-Zhu, 2022, Inflorescences of Fargesia angustissima T. P. Yi and Yushania pauciramificans T. P. Yi (Poaceae, Bambusoideae) shed light on the taxonomy of the Sino-Himalayan alpine bamboos, PhytoKeys 215, pp. 27-36 : 27

Fargesia angustissima T.P. Yi

“油竹子” (You Zhu Zi) Fig. 1

Fargesia angustissima T.P. Yi in J. Bamboo Res. 4(2): 21-22. pl. 4. 1985; Keng f. & Z. P. Wang, Fl. Reippubl. Poppularis. Sin. 9(1): 437. pl. 50, 1-8. 1996; D. Z. Li and Stapleton in Z. Y. Wu, P. H. Raven & D. Y. Hong, Fl. China 22: 85-86. 2006. L. B. Zhang in C. Y. Wu, P. H. Raven & H. Y. Hong, Fl. China Illustr. 22: 110. pl. 110: 1-7. 2007. ‘Type’: China. Sichuan: Wenchuan County, Genda Township, 1550 m alt., live on limestone slope, 22 Sept. 1974, T.P. Yi 74450 (holotype, SCFI!); ibid., 31°4.27'N, 103°19.64'E, 1434 m alt., 23 Dec. 2021, WL2021001 (epitype designated here, KUN, 1546903!).

Yushania ferax angustissima ≡ Yushania ferax subsp. angustissima (T.P. Yi) Demoly in Bambou. Bull. A. E. B., Sect. France. 46: 8. 2005.

Borinda angustissima ≡ Borinda angustissima (T.P. Yi) Stapleton in Sida. 22(1): 332, 2006.

Description.

Culms densely unicaespitose, 4-7 m tall, 1-2 cm in diameter; internodes terete, 28-35 cm long, glabrous, initially white powdery, longitudinal ribs very prominent; culm walls 1.5-2.5 mm thick; sheath scars prominent. Buds oblong. Branches 5-10 per node, slender. Culm sheaths persistent or gradually deciduous, much longer than internodes, distantly papery and narrowly banded, abaxially sparsely brown setulose, margins initially densely ciliate; auricles absent; oral setae 3-5, 5-7 mm long; ligules ca. 1 mm tall; blade reflexed, linear, narrower than apex of sheath, margins usually serrulate, readily deciduous. Foliage leaves 3-5 per branchlet; auricles absent; oral setae 5-8, 2-3 mm long; ligules convex, ca. 0.5 mm tall, external ligule pubescent; blades (1.7) 3.4-9.5 × 0.3-0.7 cm, narrowly lanceolate, abaxially proximally pubescent, second veins 2 (3) pairs, transverse veins distinct.

Flowering branches 18-60 cm long, with secondary branches; raceme composed of 1-3 spikelets, open to dense, flowering branchlet with terminal leaves 1-2, gradually deciduous, subtended by slightly inflated foliage-leaf-like sheaths, initially stretching out from one side of the sheaths; axes terete, glabrous, usually with a bract at the base of pedicels, bract lanceolate, 5 mm long. Spikelet purple-green to dark purple, 2-4 cm long, 7-10 mm wide, clustered closely; pedicels slender, curved or undulate, glabrous, 7-15 mm long; florets 2-8, 1.5-2 cm long; rachilla internode 2 mm long, expanded and pubescent at apex. Glumes 2, papery, apex acuminate, the first one narrowly lanceolate, 9-12 mm long, 2 mm wide, pubescent, apically awned, ca. 3 mm long; the second one ovoid-lanceolate, 11-15 mm long, ca. 2 mm wide, pubescent, apically awned, ca. 5 mm long. Lemma papery, ovoid-lanceolate, 15-19 mm long, 4-5 mm wide, abaxially scabrous, densely white setose, apically awned, 5-6 mm long; palea shorter than lemma, thinly papery, 5-10 mm long, 2-keeled, sulcate between keels, upper part of keels ciliate, apex obtuse. Lodicules 3, membranous, transparent, elliptical-triangular, margins ciliate. Stamens 3, filaments free, anthers yellow, gradually dark purple, ovary long-ovoid, glabrous. Stigmas 3, plumose. Caryopses oblong, dark brown, ventrally grooved, 6-9 mm long, ca. 1-2 mm in diameter, glabrous, apex with persistent style.

Phenology.

New shoots May to August. Flowering December to April; fruiting May to June.

Distribution and habitat.

Fargesia angustissima is known from Dujiangyan, Wenchuan and Chongzhou of western Sichuan, and Beichuan and Pingwu of northwestern Sichuan, and mainly occurs on the steep limestone slope or along the stream at an elevation of 800-1800 m.

Additional specimens examined.

China. Sichuan: Beichuan County, Caijiaping, near Xiaozhaizigou Nature Reserve , 09 Nov. 2017, Y. X. Zhang 17142 (KUN!) .

Figures

Figure 1. Fargesia angustissima T. P. Yi A habitat, showing flowering population B branches and internode C clum D branchlet, showing foliage leaves E culm sheath F flowering branches G inflorescence H anatomy of florets I fruit.