Fimbristylis minuticulmis X.F. Jin & C.Z. Zheng, 2017

Fimbristylis minuticulmis X.F. Jin & C.Z. Zheng View in CoL , sp. nov. ( Fig. 3 View FIGURE 3 : A–D; Fig. 4 View FIGURE 4 : A & B).

Species nova Fimbristylo diphylloidi Makino affinis est, a qua culmis 2–12 cm altis, foliis multo brevioribus, spiculis lati-ovoideis, apice obtusis, stigmatibus 2, squamis apice acutis, nuculis biconvexis differt.

Type: China. Zhejiang, Longquan County, Zhulong Township, in field margins, elevation 800 m, 30 Oct. 1980, Hangzhou Bot. Gard. Exped. 22072 (holotype, HTC! ; isotype, HHBG! ).

Annual herbs. Rhizomes absent. Culms caespitose, inconspicuously trigonous, glabrous, 2–12 cm tall, with 2–4 bladeless sheaths at base; sheath mouth obliquely truncate, sparsely ciliate. Leaves much longer than culms; blades 1–1.5 mm wide, flat, acute at apex, scabrous on upper margin; sheath 1–6 cm long, mouth obliquely split, reddish brown; ligule truncate, glabrous. Involucral bracts scale-like, ovate, 2–2.5 mm long, long-awned at apex. Inflorescence simple or compound, 1–2 × 0.8–2 cm. Spikelets 4–7, broadly ovoid, obtuse at apex, 3–5 × 2–3 mm, 20–40-flowered. Scales ovate, pale brown, 2–2.3 mm long, acute at apex, narrowly hyaline on margin, with 3 green veins; stamen 1; anthers 2–2.5 mm long. Style ca. 0.7 mm long, thickened to a conical base, glabrous; stigmas 2, slightly longer than style. Nutlets broadly obovoid, biconvex, pale yellow, ca. 0.8 mm long, ca. 0.5 mm in diam., irregularly hexagonal and inconspicuously vertically ribbed and verruculose. Fl. and fr. in October to November.

Etymology —The specific epithet refers to its short culms, only 2–12 cm tall.

Paratypes — China. Zhejiang, Longquan County, Badou , 10 November 1984, anonymous 0850 ( ZJFC) ; Yongjia, Mount Sihai, Taiping , roadsides, 21 October 1989, C. S. Ding & G. Y. Li 1537 ( ZJFC) .

Observations —Both Fimbristylis diphylloides Makino ( Makino & Nemoto 1925: 1389) and the new species have the nutlets broadly obovoid, with the epidermal cells irregularly 4–6-gonal, slightly convex ( Fig. 4 View FIGURE 4 ). Fimbristylis minuticulmis has biconvex nutlets and 2 stigmas, whereas F. diphylloides has obtusely trigonous nutlets and 3 stigmas ( Fig. 4 View FIGURE 4 : A, C).

Note —The new species is similar to Fimbristylis diphylloides Makino in having culms lateral, with bladeless sheaths at the base and scales spirally imbricate, but differs in having culms only 2–12 cm tall, much shorter than the leaves, spikelets broadly ovoid, obtuse at apex, stigmas 2, scales acute at apex, and nutlets biconvex. In Fimbristylis diphylloides , the culms are 15–50 cm tall, longer than or equal to the leaves, spikelets long-ovoid or ovoid, acute at apex, stigmas 3 or rarely 2, scales obtuse at apex, and nutlets obtusely trigonous or rarely biconvex.