橘草 ju cao

Andropogon goeringii Steudel, Flora 29: 22. 1846; A. nar-dus Linnaeus var. goeringii (Steudel) Hackel; Cymbopogon goe-ringii var. hongkongensis Soenarko; C. nardus (Linnaeus) Rendle var. goeringii (Steudel) Rendle; C. tortilis (J. Presl) A. Camus subsp. goeringii (Steudel) Koyama; C. tortilis var. goeringii (Steudel) Handel-Mazzetti.

Perennial; basal sheaths orange inside, lax, curling when dry. Culms tufted, slender, 50–100 cm tall, 1–2.5 mm in diam., nodes glabrous or puberulous, often farinose. Leaf sheaths smooth, glabrous; leaf blades linear, 15–40 × 0.3–0.5 cm, glabrous, margins scabrid, base gradually narrowed, apex finely acuminate; ligule 1–3(–4.5) mm. Spathate compound panicle narrow, 15–30 cm, 2 tiers of branching; spatheoles 1.5–2.2 cm; racemes often purplish, (1.3–)1.5–2 cm, rachis internodes and pedicels 2–3.5 mm, margins ciliate; pedicel of homogamous pair not swollen. Sessile spikelet narrowly obovate, 4.5–6 × 1.2–1.7 mm; lower glume flat or slightly concave toward base, smooth or slightly wrinkled, sharply 2-keeled throughout, keels broadly winged above middle, wings 0.25–0.45 mm wide, (1–) 3–5-veined between keels; upper lemma 2-lobed; awn (0.8–)1–2 cm. Pedicelled spikelet 4–6.5 mm. Fl. and fr. Jul–Oct. 2n = 20.

Grassy slopes, roadsides; below 1500 m. Anhui, Fujian, Guizhou, Hebei, Henan, Hong Kong, Hubei, Hunan, Jiangsu, Jiangxi, Shandong, Taiwan, Yunnan, Zhejiang [Japan, S Korea].

Cymbopogon goeringii and C. tortilis form an intergrading complex, and the former species is sometimes treated at infraspecific rank under the latter. Cymbopogon goeringii tends to have a slightly more northern distribution and can usually be distinguished by its longer racemes of larger, often purplish spikelets.

A local variant in Hong Kong has racemes, spikelets, and awns at the lower end of the size range, perhaps due to introgression from Cym-bopogon tortilis, but has the obovate lower glume and broadly winged keels of C. goeringii. It has been distinguished as var. hongkongensis, but scarcely merits separate status.

The name "Cymbopogon eugenolatus L. Liu" (Fl. Reipubl. Popularis Sin. 10(2): 206. 1997) has been applied to another variant with intermediate measurements, but was not validly published because no Latin description was provided. The specimen on which it was based has not been seen.