Huchimingia ichthyochtona (Drake) Z.Q. Song, 2022

Song, Zhu-Qiu, Li, Shi-Jin & Mattapha, Sawai, 2022, Huchimingia, a new genus segregated from Millettia (Leguminosae, Millettieae) based on morphological and molecular evidence, Phytotaxa 532 (1), pp. 37-56 : 47-48

1. Huchimingia ichthyochtona (Drake) Z.Q. Song , comb. nov.

≡ Millettia ichthyochtona Drake, J. Bot. (Morot) 5(12): 187. 1891 ( Drake 1891).

Type: VIETNAM. Tonkin, Ha Tay , env. de Tu Phap , Sep 1886, B. Balansa 2236 (lectotype, designated by Lôc and Vidal 2001, pg. 104: P! [P02141811] ; isolectotypes: K! [K000848753], P! [P02141809, P02141810, P02141812]).

Description. Trees, up to 15 m tall and 30 cm in diameter at breast height, branched at lower part; bark grey, with white lenticels; branches of the current year pubescent, glabrescent, bearing 4–7 buds; flowering buds inserted at lower part. Buds axillary, rounded, green; scales 6–8, broadly ovate, ciliate. Stipules linear to narrowly oblanceolate, 15–20 × 1.5–3.5 mm, brown, caducous, ciliate. Leaves alternate, imparipinnate; stipels absent; leaflets 5–9 (usually 7), papery, opposite or rarely subalternate, obliquely ovate, 2.9–5.7 × 1.5–2.9 cm, base cuneate, apex acuminate, glabrous on both surfaces; terminal leaflet largest, oblanceolate; lateral leaflet asymmetric at base; the lowest leaflet smallest, ovate-triangular; principal lateral veins 5‒8 on each side of midvein, curved apically near margins. Pseudoracemes 2.3–15 cm long (usually 4–7 cm), inserted in the leafless axil of leaf on the lower part of previous branchlets, without distinct brachyblasts, laxly flowered; rachis pubescent, bearing 12–20 flowers, always with 2 flowers each node; bracts subtending the indistinct brachyblasts membranous, narrow oblong, ca 12 × 4 mm, dark brown, pubescent; floral bracts filiform, ca 8 mm long, dark brown, inserted at the base of pedicel; bracteoles absent or strongly reduced at the middle of the pedicel; pedicel 1.0– 1.8 cm long, slender, pubescent. Flowers 1.5–1.9 cm long; receptacle hollow, with distinct longitudinal ridges outside; calyx campanulate, 5–6 mm high, pubescent outside and slightly hairy inside, 4-toothed; the upper lobe broadly triangular, 5.8 × 2.0 mm; lower 3 lobes triangular, 2.3–2.7 × 2.5 mm; petalswhite, glabrous; standard petal suborbicular, reflexed, 12.5–13.7 × 13.9–14.6 mm, apex emarginate, with a yellow-green patch at base, without basal calluses, with a 3–4 mm long claw; wing petals oblong, 12.0–13.5 × 5.5–6.2 mm, base auriculate, apex obtuse, with a 4.0– 5.3 mm long claw; keel petals falcate, 10.3–10.7 × 5.2–5.4 mm, base truncate, apex obtuse, pocketed at side, with a 5.0– 5.4 mm long claw; stamens 10, pseudo-monadelphous; filaments connate into a tube, with 2 fenestrae at base; anthers oblong, ca 0.6 × 0.3 mm; disk absent; ovary linear, 14 mm long, villous only on ventral suture side and glabrous at other part, with 2 ovules at upper part, stipitate; stipe 3.3–4.0 mm long, glabrous; style ca 4 mm long, incurved, glabrous; stigma small, capitate. Pod tardily dehiscent, falcate-oblanceolate, flat, 11.2– 14.8 × 2.9–3.7 cm, thinly woody, smooth, reticulate with veins, apex beaked, stipitate; stipe 0.5–0.9 cm long, ca 2 mm broad, glabrous; fruiting pedicel 1.2–1.8 cm long, ca 2 mm wide, glabrous. Seeds 1–2, pale to deep brown, ellipsoid, compressed, 1.3–1.6 × 1.2–1.4 × 0.5 cm, shiny, with a thin testa and a well-developed aril.

Seedling morphology. Seedling epigeal, phanerocotylar. Cotylendons 2, opposite, spreading above soil-level and escaping the testa after germination, suborbicular, ca 2.1 × 1.6 × 0.3 cm, sessiles, fleshy, green, half-open, glabrous, long persistent, turned yellow and shed on about 20th day after germination. Hypocotyl 4–8 mm long, pale green, subglabrous. Epicotyl 8–13 cm long, green, pubescent. First two eophylls opposite, 7–9-foliolate; leaf rachis 5.2–7.4 cm long, villous; leaflets opposite, ovate to lanceolate, 3.7–6.0 × 1.4–2.4 cm, base truncate to rounded, apex acute and obtuse, dense appressed whitish villous on both surfaces. Stipules linear, ca 3.5 × 0.5 mm, villous, shed on about 20th day after germination. Stipels absent.

Distribution and ecology. This species is known from China (Guangxi and Yunnan), Thailand (Lampang), and Vietnam (Bac Kan, Cao Bang, Ha noi, Hoa Binh, Lao Cai, Nghe An, Ninh Binh, Thai Nguyen, Thanh Hoa, and Tuyen Quang), at an altitude of 100– 600 m. The species appears to be flowering before or as leaves expand. It flowers from February to April, and fruits from May to the next April. It may be considered as ‘Least Concern’ (LC) according to IUCN criteria ( IUCN 2012).

Notes. Wei and Pedley (2010) recorded this species with branched pseudoracemes; however, based on herbarium specimens and living individuals, we observed this species as having unbranched pseudoracemes, which have quite indistinct brachyblasts with two flowers at each brachyblast. This species is easily recognized by 5–9-foliolate leaves, asymmetric lateral leaflets, leafless pseudoracemes, 1.0– 1.8 cm long flowering pedicels, 2-ovuled ovary, and falcateoblanceolate and woody pods with 1–2 seeds.

Here, we describe the seedlings of this species for the first time, which show that it has epigeal and phanerocotylar cotylendons ( Fig. 4 ). This seedling type is consistent with previous observations in the tribe Millettieae ( De Vogel 1980, Sousa and de Sousa 1981, Khan et al. 2015). However, the eophyll (first leaves) of Huchimingia ichthyochtona appears to bear more leaflets (7–9 leaflets), while eophylls with one or three leaflets are usually found throughout the tribe, including in Hesperothamnus , Piscidia , Tephrosia , and most species of Lonchocarpus ( Sousa and de Sousa 1981) . In the genus Millettia, Khan et al. (2015) found that M. pinnata had 1-foliolate eophyll. Our observations showed M. leptobotrya Dunn (1912: 189) , M. xylocarpa Miquel (1855: 157) and M. versicolor Baker (1871: 129) also have 1-foliolate eophylls, while M. macrostachya Collett & Hemsl. has a 3-foliolate eophyll.

Additional specimens examined. CHINA. Guangxi: Ningming, 7 Aug 1977, Han-Hua Fang 2-0177 (GXMI [GXMI017749]), 500 m, 9 May 1944, S. H. Chun 5069 (IBSC [0192019]). Yunnan: Yuanyang, 380 m, 12 Nov 1973, De-Ding Tao 1371 (HITBC [HITBC0014887], KUN [0617783, 0617785], PE [00410851]), 330–600 m, 1 Jun 1974, Lvchun Exped. 1368 (HITBC [HITBC0014888], KUN [0617782, 0617784]), 500 m, 11 Oct 1991, Guo-Da Tao 47582 (HITBC [HITBC0014889, HITBC0014886]), 11 Oct 1991, Guo-Da Tao 47599 (HITBC [HITBC0014890, HITBC0014885]), 340 m, 22 May 2015, Hua Peng 8133 (HITBC); Gejiu, 4 Apr 2015, Li-Chun Yan & Lu Li 823 (HITBC); Jinping, 520 m, 20 Dec 1951, P. I. Mao 568 (KUN [0617786, 0617788]), 350 m, 18 Apr 1956, China-Soviet Union Exped. 339 (KUN [0617787], PE [00410854]); Hekou, 160 m, 24 Jul 1959, Wei-Xin Liu 324 (KUN [0617777]), 17 May 1966, Nongye Exped. s.n. (KUN [0617781, 0617780, 0617779]), 27 Apr 1940, Hong-Da Zhang 1374 (IBSC [0162106], SYS [SYS00046922]), 140 m, 20 May 1953, Min-Yuan Xiao 9 (KUN [0617767], PE [00410852]), 13 Apr 1953, 450 m, Ke-Hua Cai 341 (NF [NF2010212]); Xishuangbanna Botanical Garden, cultivation, 9 Mar 2002, Qing-Hua Li 544 (HITBC), 27 Oct 2016, Qian Xia 63 (IBSC), 29 Oct 2016, Qian Xia 75, 80 (IBSC), 507 m, 18 Aug 2020, Zhu-Qiu Song 202029 (IBSC), 28 Mar 2021, Zhu-Qiu Song 2021001 (IBSC). THAILAND. Lampang: Me Ta, 300 m, 13 Feb 1921, A. F. G. Kerr 4840 (BK [210714], BM, E, K [K001415902]). VIETNAM. Bac Kan: Kim Hy, Eberhardt 4686 (P [P02753788, P02753789]), Bach Thong District, 21 Mar 1998, T. N. Ninh & N. Q. Binh 9816 (L [L.2049187]); Cao Bang: Nam Ha, 1892, R. P. Bon 5305 (K [K001415904], P [P02753912]); Ha noi: 1 May 1962, Nguyen Dang Khoi 161 (HN [0000028116]), Mar 1961, Nguyen Dang Khoi 162 (HN [0000028088]), 29 Mar 1963, Nguyen Dang Khoi 6973 (HN [0000028115]), Ha Tay, Jan 1965, EXP. Sino-Vietnam 3789 (HN [0000028110], HN [0000028111]), Ha Tay, Sep 1886, B. Balansa 2237 (K [K000848752], P [P02141813, P02141814, P02141815, P02141816], L [L.2049188, L.2049190]), Apr 1909, C. d’Alleizette s.n. (L [L.2049189]), Tonkin Bot. Garden. 24 Sep 1921, F. A. McClure 879 (SYS [SYS00046923], NAS [NAS00391104]); Hoa Binh: Le Van Quy & Quynh s.n. (HN [0000028114]), Yen Thuy, 9 Apr 1970, Le Van Quy 97-52 (CPNP [02080]), Luong son, 6 Jun 1885, B. D. Binh B765 (K [K001415903]), Hanoi to Hoa Binh, Mar 1933, A. Petelot s.n. (NY, P [P02753781, P02753785]), May 1933, A. Petelot s.n. (NY), Jan 1935, A. Petelot s.n. (A, P [P02753769, P02753782], PE [00413280]); Lao Cai: Trinh Thuong, 100 m, 7 Jan 1931, Poilane 18770 (BKF [SN130619], P [P02753780]), Bao Nhai, 8 Dec 1935, Poilane 24988 (P [P02753778]); Nghe An: Nghia Huang, 19 May 1914, F. Fleury 32575 (BKF [SN130621], P [P02753787, P02753791]); Ninh Binh: Cuc Phuong National Park, Le Van Quy s.n. (CPNP [02061]), Anonymous s.n. (CPNP [02062]), Le Van Quy s.n. (CPNP); Thai Nguyen: Dong Hy, 21 Jun 2001, T. N. Ninh & P. H. Hoang 11449 (L [L.2049186]); Thanh Hoa: Ke Bon, Donnat 38147 (P [P02753910]), Sep 1917, Donnat 38129 (P [P02753911]), 2 Aug 1929, Poilane 16536 (BKF[SN130617], L [L.2049185], P [P02753779]), Thach Thanh, 10 Dec 2015, Shi-Jin Li 4066 (IBSC); Tuyen Quang: Tuyen Quang, Eberhardt 4013 (P [P02753790]), 30 Apr 1918, F. Fleury 37428 (L [L.2049184], P [P02753783, P02753784, P02753786]); Without precise locality: Poilane s.n. (P [P02753776]), Poilane 26305 (P [P02753777]).

Figures

FIGURE 4. Seedling of Huchimingia ichthyochtona (Drake) Z.Q. Song. A 10-day old seedling, showing epigeal and phanerocotylar cotylendons B 14-day old seedling, showing the first two eophylls with 7–9 leaflets C–E 10-day old seedling, showing the stipules and leaflets with dense appressed hairs F–H 28-day old seedling, showing position of dropped cotylendons (red arrow), dropped stiuples (G), and no stipels (H). Scale bars = 8 cm. Photograph by Zhu-Qiu Song.