生活型

herb

形態特徵

• Usually stout well branched subglabrous or finely puberulent annual herb 15–100 cm tall.
• Leaves narrowly elliptical to narrowly lanceolate, 1–10 cm long, 0.4–2.5 cm wide, narrowly cuneate at the base, the apex acuminate; submarginal vein not prominent; petioles 0.3–1.5 cm long.
• Sepals 4–6, deltoid, 1.5–4.5 mm long, 0.4–1.5 mm wide, puberulent, apiculate. Petals yellow, obovate, 1.8–2 mm long, 0.7–1.2 mm wide. Stamens as many as sepals; filaments 0.5–1.2 mm long; anthers 0.4-0.7 mm long, shedding pollen directly onto the stigma at anthesis. Pollen grains shed individually. Disc elevated about 0.5 mm, with a sunken glabrous or white hairy nectary opposite the base of each petal. Style 0.5–1.2 mm long; stigma globose.
• Capsule relatively thin-walled, puberulent, 10–28 mm long, 1–2 mm thick, terete, light brown, subsessile. Seeds in one or two rows in each locule of the capsule, diagonal, light brown with darker thin red-brown stripes, elongate-ovoid, 0.7–1.4 mm long, 0.3-0.4 mm thick, apiculate at one end; raphe inconspicuous; each column of seeds, which may include two rows, loosely enclosed in a column of spongy light brown endocarp from which the seeds fall easily, but which also separates into 1- or 2-seed units.
• 2n = 48. Plants usually flower in the summer. Those persisting through winter often bear cleistogamous flowers that set smaller, narrowly elliptic-lanceolate fruits (ca. 4.5–6 mm long vs. (10-)15–28 mm long in the normal, summer-flowered plants). Their sepals are smaller, ca. 1–1.2 mm long, often coalesced and enclosing the inconspicuous, vestigial petals (sometimes entirely lacking). The following specimens are representative. TAIPEI: Nankang, December 12, 1988, Leu 15. HUALIEN: Meilun, January 18, 1984, Chen s.n. The distinctions between subsp. epilobioides, with subglabrous young leaves, glabrous disc, and seeds 1–1.4 mm long, and subsp. greaxtrexii, with puberulent young leaves, white-hairy disc, and seeds 0.7–1 mm long, do not seem to hold for populations from Taiwan and are not recognized here.

物候

Flowers Jul-Jan; fruit Jul-Jan.

分布

• 台灣 : Often common in low moist places like rice paddies and at low and medium elevations.
• 世界 : Asia, from the Amur River to Korea, throughout China to Yunnan, Kwangtung, and Hainan, North Vietnam; central and southern Japan to Taiwan.

引證標本

TAIPEI: Nankang, Leu 4. ILAN: Kungkuan to Tungkang, Peng 7018. TAOYUAN: Shanchuhu, Peng 13488; Yungan, Kao 8779. HSINCHU: Yulo River, Peng 12139. MIAOLI: Touwu, Peng 5415; Yunghsing, Lin 519. KAOHSIUNG: Liukuei, Peng 11203.

引用文獻

• RAVEN, PETER H. and PENG, CHING-I, Flora of Taiwan, second edition 3: 955. 1993.  (Fl. Taiwan 2nd edit., 台灣植物誌第二版)