Hilliella rhombea D. D. Ma & W. Y. Xie, 2018

Ma, Dan-Dan, Xie, Wen-Yuan, Chen, Zheng-Hai & Xia, Guo-Hua, 2018, Hilliella rhombea (Brassicaceae), a new species from eastern China, Phytotaxa 357 (2), pp. 148-152 : 150-151

Hilliella rhombea D. D. Ma & W. Y. Xie , sp. nov. Fig. 1 , 2 , 3

Type: — CHINA. Zhejiang Province: Hangzhou City, Fuyang County, Longmen Forest Farm, valleys, alt. 560 m. 24 May 2015, W. Y. Xie & D. D. Ma FY20150510 (holotype, ZJFC, isotype ZMNH).

Annuals or biennials, 10–35 cm tall. Stems slender, branched below and above, papillate in the upper part. Basal leaves not rosulate, simple, reniform-orbicular, 1–2 × 1–2.5 cm, base deeply cordate, margin with irregular orbicular dentate, petiole ca. 4.5 cm; lowermost cauline leaves suborbicular, 3-lobed; upper cauline leaves trifoliolate, petiole 0.2–3 cm, not winged; terminal leaflet rhomboid-elliptic, 1–4 × 0.8–2.8 cm, apex mucronate, base cuneate, margin 3-lobed without apiculate callosities, petiole 0.3–2.0 cm; lateral leaflets oblique, usually unequal, margin crenate, petiole 0.2–1.0 cm. Racemes terminal or axillary, 4–40-flowered, ebracteate; rachis slender, 2–15 mm, only somewhat flexuous. Fruiting pedicels slender, horizontal or slightly reflexed, 2–6 mm, straight or slightly recurved, glabrous. Sepals 4, mauve or white, oblong, 1–1.5 mm, apex obutse. Petals mauve or white, elliptic, 2–2.5 mm, base shortly clawed, apex rounded. Stamens 6, in 2 whorls, subequal, ca. 1.5 mm, filaments slightly curved. Median nectaries absent; lateral glands 1 on each side of lateral stamen, triangular. Pistil ovate, ca. 1.5 mm, with rhombic wings, ovary 2-ovuled; style ca. 0.7 mm, flattened. Fruit rhombic-ovate, ca. 4 mm, flattened; fruiting pedicels recurved, slender; valves membranous, glabrous or sparsely papillate. Seeds 2 per fruit, brown, ovate, 1–2 mm, densely minutely papillate.

Habitat: —The forest edge and rock crevices of valley, at an elevation between 400 and 800 m.

Known distribution: —Only known from two populations in Longmen Forest Farm, Fuyang Zhejiang, China.

Additional materials examined: — CHINA. Zhejiang: Fuyang County, Huyuan town, Xin’er village, Zhongta, on rock crevices, alt. 460 m, 21 May 2014, W. Y. Xie FY20140502 ( ZJFC).

Phenology: —This new species has been observed in flowers form April to May, fruits from May to July.

Etymology: —The epithet refers to its fruit shape rhombic.

Comparison: — Hilliella rhombea is similar to H. fumarioides (Dunn 1908: 355) Y.H. Zhang & H.W. Li (Zhang 1986: 403), but can be distinguished from the latter by rhombic fruit with membranous, glabrous or sparsely papillate valves.

Figures

FIGURE 1. Hilliella rhombea (Drawn by Yi Zhang). A) flowering branch; B) basal leave; C) lower cauline leaves; D) upper stem with papillae, a: flower, b: petal, c: calyx, d: pistil, e: stamen, f: fruit, g: seed.

FIGURE 2. Hilliella rhombea (photographs by Dan-dan Ma.). A) habit; B) plant with flowers, C) flower; D) infructescence; a: petal, b: calyx, c: pistil, d: stamen, e: upper stem with papillate, f: seeds, g: fruit.—Scale bar: A = 2 cm, B = 1 cm, C, e-g = 1 mm, D = 0.5 cm, a-d = 0.25 mm.

FIGURE 3. SEM photomicrographs of seed of Hilliella rhombea sp. nova.—A: equatorial view of seed.—B: polar view of seed.—C: exine sculpture.