Hemipilia avisoides Y.Tang, X.M.Wang & H.Peng, 2022

Wang, Xue-Man, Tang, Ying, Peng, Pei-Hao & Peng, Hua, 2022, Hemipilia avisoides (Orchidaceae), a new species from Sichuan Province, China, PhytoKeys 213, pp. 1-18 : 1

Hemipilia avisoides Y.Tang, X.M.Wang & H.Peng sp. nov.

Figs 3A-D , 4 , 5 , 6A; see also Data availability

Type.

China, Sichuan Province, Aba Tibetan and Qiang Autonomous Prefecture, Songpan County, 9 June 2022, Y. Tang, X.-M. Wang & Y.-T. Zhu 235 (holotype: SZ!); ibid., 9 June 2022, Y. Tang, X.-M. Wang & Y.-T. Zhu 236 (paratype: SZ!); Maoxian County , 1 June 1958, S.-Y. Chen, Z. He, M.-F. Zhong et al. 5078 (paratype: SZ!) .

Diagnosis.

Similar to Hemipilia hui (Tang & F.T.Wang) Schuit., from which H. avisoides can be distinguished by a set of characteristics: mid-lobe involute, suboblong in apical view, 2.2 × 1.2 mm, trapeziform when flattened, smaller than lateral lobes; floral bracts 5 mm long, always shorter than ovary; leaf appressed to the substrate, adaxially green with white lines along 7-9 principal veins; stem subterranean, with one sheath at the base (Table 1 ).

Description.

Terrestrial, erect herbs, 8.5-31 cm tall. Tubers oblong, 2.5 cm long, 0.8 cm in diameter, neck with few roots. Stem subterranean, 2.7-5 cm long, 0.2 cm in diameter, with one sheath at the base. Sheath tubular, membranous, 1-2 cm long, pale yellow. Leaf appressed to the substrate, solitary, cordate, ovate or elliptic, 3-6.5 × 2-5.5 cm, apex acute, slightly fleshy, glabrous, abaxially purple, adaxially green with white lines along 7-9 principal veins, sometimes also with purple spots. Inflorescence terminal, erect, 3-14 cm long, 1-21-flowered, glabrous, dark purple. Flowers not secund, plum or purple plum, fragrant; floral bracts connivent to ovary, elliptic, 5 × 2.6 mm, shorter than ovary, apex acuminate, glabrous, dark purple; ovary curved, cylindrical, 10.5 mm long including pedicel, 1 mm in diameter, glabrous, dark purple. Dorsal sepal erect, oblong, cymbiform, 4.5 × 2.6 mm, apex rounded, sometimes concave at each side of central vein below middle, glabrous; lateral sepals spreading, obliquely ovate, cymbiform, 5.6 × 3.6 mm, apex obtuse, glabrous. Petals erect, connivent with dorsal sepal and forming a hood, apex bending similar to holding a fist in the other hand, obliquely ovate, 4 × 2.8 mm, apex obtuse, glabrous. Labellum spreading, broadly ovate when flattened, 7.1 × 5.4 mm, 3-lobed below middle, spurred, base collar-like raised on each side of spur entrance, glabrous, tinged white at base, disc dotted with purple; lateral lobes pendulous, rhombic, 3.4 × 2.5 mm, apex truncate, margin slightly undulate; mid-lobe horizontal, involute, suboblong in apical view, 2.2 × 1.2 mm, trapeziform when flattened, apex rounded or sometimes apiculate; spur horizontal, straight or curved upwards, cuneate, 9 mm long, ventrally carinate along central axis, entrance 2.5 mm wide, apex swollen, obtuse, 2.7 mm wide; anther reclined, 2.8 mm long, 2-locular, locules parallel and closely spaced, aubergine; pollinia 2, sectile, ovate, 1.2 × 0.7 mm; caudicles cuneate, 1.2 mm long; viscidia 2, closely spaced, oblong, transparent, each enclosed within a separate bursicle; bursicles formed by folding of rostellar arms, oblong, 0.6 × 0.3 mm; rostellum median lobe triangle, 0.7 mm long, lateral lobes grooved; stigma ventral, lobes 2, divergent, lamelliform, 1.2 × 0.5 mm, with hairs at base; auricles 2, each placed laterally at base of anther and behind collar of labellum base, 0.5 mm long.

Flowering.

Peaking in early June.

Distribution and habitat.

Hemipilia avisoides is currently known from two localities in Songpan County, which are ca 11.2 km apart along the Minjiang River Valley and one locality in Maoxian County according to the collection by S.-Y. Chen et al. in 1958. Individuals of the new taxon occur under arid-valley shrubs and on moss-covered rocks (see Discussion).

Etymology.

Latin avis, bird, and suffix - oides, similar, alluding to appearance of flower arrangement simulating flying birds with flapped wings.

Chinese name.

雁字舌喙兰 (Chinese Pinyin: yànzì shéhuìlán).

Additional specimens examined.

Hemipilia avisoides : China, Sichuan Province, Aba Tibetan and Qiang Autonomous Prefecture, Songpan County, 30 June 2013, Y. Tang 151 (KUN!). Hemipilia hui : China, Sichuan Province, Ganzi Tibetan Autonomous Prefecture, Kangding City, 18 June 2022, Y. Tang, X.-M. Wang, W.-Q. Yuan & Y.-T. Zhu 237 (SZ!); ibid., 17 June 2017, Y.-L. Peng, Q. Yu & L.-L. Li THP-KD-1390 (CDBI!); ibid., 13 June 2014, Y. Tang 199 (KUN!); ibid., 28 May 1981, Z.-J. Zhao, J.-B. Shi & D.-G. Fan 114262 (SZ!); Luhuo County, 12 August 2005, D. E. Boufford, J.-H. Chen, K. Fujikawa, S. L. Kelley, R. H. Ree, H. Sun, J.-P. Yue, D.-C. Zhang & Y.-H. Zhang 34770 (A!); Xiangcheng County, 15 July 2004, D. E. Boufford, J.-H. Chen, S. L. Kelley, J. Li, R. H. Ree, H. Sun, J.-P. Yue & Y.-H. Zhang 30764 (A!); Daofu County, 10 June 1996, J.-S. Yang 91-270 (IBSC!; PE!); Xinlong County, 28 June 1974, Z.-S. Qin 06383 (CDBI!); ibid., 27 June 1974, Z.-S. Yu 06409 (CDBI!); Yajiang County, 15 June 1961, S. Jiang 05196 (KUN!). China, Sichuan Province, Aba Tibetan and Qiang Autonomous Prefecture, Xiaojin County, 2 July 2013, Y. Tang 156 (KUN!); ibid., 21 May 1959, Xiaojin Zu 0130 (SZ!); ibid., 21 May 1957, J. Zhou 34 (IBSC!); Maerkang City, 16 May 1957, X. Li 71047 (PE!; SZ!). China, Gansu Province, Longnan City, Wenxian County, 12 May 2007, Baishuijiang Caijidui 4839 (PE!); ibid., 9 May 2007, Baishuijiang Caijidui 4514 (PE!); Wudu District, 15 June 1959, Z.-Y. Zhang 4390 (WUK!); ibid., 5 June 1959, Z.-Y. Zhang 3379 (WUK!); ibid., 30 May 1959, Z.-Y. Zhang 3180 (PE!; WUK!). China, Gansu Province, Gannan Tibetan Autonomous Prefecture, Zhouqu County, 27 May 1999, Bailongjiang Exped. 1408 (PE!). China, sine loc., 1959, Chuan Jing A 0130 (KUN!); sine loc., July 1907, E. H. Wilson 1762 (the second individual from left on the sheet: AMES!).

Conservation status.

Hemipilia avisoides seems narrowly distributed within the arid valley in the upper reaches of Minjiang River (see Discussion), with few populations and individuals being found. The habitat of H. avisoides could be easily disturbed by development as it is close to roads and villages. According to the IUCN Red List Categories and Criteria ( IUCN Standards and Petitions Committee 2022), for H. avisoides , the area of occupancy (AOO) is 8 km2, the number of locations is one and the area, extent and/or quality of habitat are likely to decline due to disturbances. Moreover, the number of mature individuals is less than 50. Therefore, H. avisoides is here tentatively assigned to the IUCN category CR B2ab (Critically Endangered).

Figures

Figure 3. Comparisons between living plants of Hemipilia avisoides sp. nov. and H. hui in the wild A-D habit, flowers, leaf and habitat of H. avisoides E-H habit, flowers, leaf and habitat of H. hui. Photographs A-H by Y. Tang.

Figure 4. Floral morphology of Hemipilia avisoides sp. nov., based on 3 D mesh model reconstructed by micro-CT data A inflorescence with uppermost two flowers B ventral and dorsal views of floral bract C lateral view of ovary, with floral bract at base D ventral and dorsal views of dorsal sepal E ventral and dorsal views of lateral sepal F ventral and dorsal views of petal G ventral view of gynostemium H ventral and dorsal views of labellum I lateral views of labellum. The 3 D model in STL format is available on Zenodo (https: // doi. org / 10.5281 / zenodo. 6832154).

Figure 5. Specimen of S. - Y. Chen, Z. He, M. - F. Zhong et al. 5078 (SZ!) identified as Hemipilia avisoides in this study. Key features, which would facilitate the identification of this specimen, are highlighted and arrowed in yellow.

Figure 6. Leaves of Hemipilia avisoides sp. nov. and some related species in H. sect. Hemipilia sensu Tang et al. (2015) A H. avisoides B H. thailandica C H. hemipilioides D H. brevicalcarata E H. galeata F H. cordifolia. Photographs A-F by Y. Tang.