絹毛鳶尾

Banksea speciosa J. König in Retzius, Observ. Bot. 3: 75. 1783; Costus speciosus (J. König) Smith var. leiocalyx (K. Schumann) Nakai, J. Jap. Bot. 17(4): 197-198. 1941 Costus speciosus (J. König) Smith var. hirsutus Blume, Enum. Pl. Jav. 1: 61. 1827; K. Schumann in Engler, Bot. Jahrb. 27: 343. 1899; in Engler, Pflanzenfam. 20(Ⅳ. 46): 398. 1904; Nakai, J. Jap. Bot. 17(4):198-199. 1941. Costus formosanus Nakai, J. Jap. Bot. 17(4): 199. 1941. Costus speciosus (J. König) Smith var. formosanus (Nakai) Ying, Q. Jour. Chin. For. 21(2): 117. 1988.

Stems 1–3 m, bearing 2 or 3 branches , apex branched and spirally twisted. Petiole 5–7 mm; leaf blade ovate, oblong or lanceolate, 15–20 6–10 cm, abaxially glabrous to densely sericeous, base subrounded, apex acuminate or caudate-acuminate; leaf sheath tubular, 4-5 cm, margin hairy. Inflorescences a capital spike, terminal, ellipsoid or ovoid, 5–15 cm; bracts green tinged with bright red, ovate, ca. 2 cm, leathery, pubescent; bracteoles pale red, 1.2–1.5 cm, keeled. Calyx 1.8–2 cm, leathery, apex 3-lobed, lobes rigid and densely sericeous at apex, red after flowering.. Corolla tube shorter than calyx, lobes oblong-elliptic, ca. 5 cm, apex white or pinkish. Labellum white, trumpet-shaped, 6.5–9 cm, apex toothed and crisped, with edges overlapping. Fertile stamen petaloid, white with orange-yellow base, urceolate, ca. 4.5 1.3 cm, pubescent. Capsules red, globose, ca. 1.5 cm, slightly woody. Seeds black, glossy, ca. 3 mm long.

Nantou Hsien: Jiji, Chuan-chieh Chen 576 (TNU); Shuili Hsiang, Wen-pen Leu 1553 (TNU). Chiayi Hsien: Tsengwen Reservoir, Chi-cheng Liao 1563 (TNU); same loc., Yu-chuan Lu 1645 (TNU). Kaohsiung Hsien: Tien-Liao, Mei-fang Kao 1776 (TNU). Pingtung Hsien: Taiwu Hsiang, Chao-chien Wang 463 (TNU); Maolin Hsiang, S. Z. Yang 20079 (TNU).

Widely distributed throughout tropical Asia. Common in the central and southern Taiwan, often in thickets.