Rohdea rotiformis H. Z. Feng 2023, sp. nov.

Type:— CHINA. Sichuan: Tibetan and Qiang Autonomous Prefecture of Ngawa, Wenchuan country, alt. 1700 m, 15 April 2022, H. Z. Feng 2022–041 (holotype, CSH!).

Diagnosis:—This species is most similar to R. urotepala in sharing character of at orifice of tube developing annulus, but differs mainly by the annular appendage upper surface smooth, tube 2–5 mm; lobes spreading, rotate, deltoid-ovate, margin entire.

Description:—Herb perennial. Stem suberect or oblique, terete, unbranching, to 30 cm long, 2 cm in diameter, fleshy, apical part densely covered with foliar bases. Roots wiry, rigid, semi-woody. Cataphylls 2–3 at base of annual tuft of foliage leaves, equitant, narrowly triangular, acuminate, 3–6 cm long, 1.0– 1.5 cm wide, abruptly widened at base to 5 cm wide. Leaves 4–6, sub-distichous, equitant, oblique to recurved, narrowly oblong elliptic or narrowly elliptic, 30–45 cm long, 2–4 cm wide, gradually tapering to thick, conduplicate petiole-like basal part, acuminate to subcaudate at apex, serrated, undulate, leathery, uniformly glossy grassy green; lateral veins 6, raised on adaxial, white. Peduncle erect, ca. 4.5 cm long, ca. 5 mm in diameter. Inflorescence a terminal, cylindric, spike 7–8 cm long, ca. 0.5 cm in diameter. Floral bracts very small, one per flower; bracts located below flower, deltoid or ellipse, 1 mm long, 1.5 mm wide. Flowers sessile on shallow pits of rachis, (8)9–10(11) mm across, with light specific scent. Perianth broadly campanulate, yellowish green, glabrous; with a cushionlike, ringed, fleshy appendage in throat, segments narrowly ovate-triangular, 5–7 mm long, 2–3 mm wide, entire, radial. Stamens 6; filaments arising from the base of perianth tube, very short ca. 0.3 mm long, fleshy. Pistil 1, light green; ovary superior, hexagonal in cross section, slightly 3- sulcate longitudinally, ca. 1.5 mm in diameter, 3-locular, each locule containing 1 ovoid ovule; stigma subsessile, trisected.

Phenology:—Flowering from April to May. Initial development of fruits was observed from July to November and the fruit persistent until March of the next year.

Etymology:—The specific epithet refers to the rotiform perianth lobes, which is the most significant character differentiating the species from all known congeners.

Habitat:—The new species was found growing on the banks of stream in cooled and wet semi-evergreen forests.

Distribution:— CHINA. Chongqing, Nanchuan country, Jinfoshan. Sichuan. Chengdu city, Chongzhou country; Tibetan and Qiang Autonomous Prefecture of Ngawa, Wenchuan country; Songpan country; Mao country. Leshan city, Mabian Yi Autonomous country. Mianyang city, Beichuan country, Pingwu country.

Taxonomic relationship:—The comparison of morphology among all known species of Rohdea indicates that R. rotiformis superficially resembles to R. urotepala However, R. rotiformis differs from R. urotepala by the perianth throat appendages have smooth surface (vs. with papillose appendage in throat), perianth segments rotiform, margin entire (vs. incurved, acuminate-cuspidate, margin serrate), stigma subsessile (vs. style 2 mm long). This species appears to be descended from the ancestral lineage of R. fargesii Baillon (1893: 1114) var. tsinlingensis (Tanaka 2010: 11) Deng (2019: 127) (Fig. 5). The annulus of the perianth of R. rotiformis and R. urotepala must be a derived character state that maybe formed by connexion and expansion of the distinct minute vertical coroniform appendage of R. fargesii var. tsinlingensis. The earliest ancestor of this type may be R. chlorantha (Baillon 1893: 1115) Tanaka (2010: 31) (Fig. 6) which possesses the perianth tube without annulus but densely lamellate internally and at orifice, veins running into each lobe prominently incrassate dorsally. This is very different from R. verruculosa (Chen 1987: 69) Yamashita & Tamura (2004: 369) (Fig. 7) which possesses the stamens outside the annulus and the annulus of R. verruculosa derived from the dilated decurrent parts of staminal filaments (Tanaka 2010). To add, the filaments of R. chlorantha, R. fargesii var. tsinlingensis, R. rotiformis and R. urotepala are very short that cannot widen. Additionally, the flowers of R. urotepala have two connate conditions and the connate flower has 10 stamens which assemble to some species of Asparagus L. (Fig. 3).

Other specimens examined: CHINA. CHONGQING. Nanchuan country, Anonymous 3046 (PE00035409). SICHUAN: Chengdu city, Chongzhou country, W.B. Ju, D.K. Zang & M. Li AZH01006 (CDBI0254657). Mianyang city, Beichuan country, Qingpian town, 2 May 2022, H.Z. Feng 2022–051 (stored in Zaozhuang University); Mao country, G.Q. Li & Z. P. Tang 489 (CDBI0099709); Pingwu country, Huya town, 4 May 2022, H.Z. Feng 2022–059 (stored in Zaozhuang University). Tibetan and Qiang Autonomous Prefecture of Ngawa, Songpan country, Baiyang town, 2 May 2022, H.Z. Feng 2022–054 (stored in Zaozhuang University). Leshan city, Mabian Yi Autonomous country, T.Tang 22895 (PE00035410). SICHUAN, No exact location, Z.X. Zhao 340 (PE00593261); Anonymous 3046 (PE00593265); T. Tang 22825 (PE00593260).