Alpine Enchanter’s Nightshade

In Great Britain and/or Ireland:
Foodplant / parasite
Erysiphe circaeae parasitises Circaea alpina

Foodplant / parasite
telium of Puccinia circaeae parasitises live stem of Circaea alpina
Remarks: Other: uncertain

Foodplant / parasite
hypophyllous telium of Pucciniastrum circaeae parasitises live leaf of Circaea alpina
Other: minor host/prey

Circaea alpina is a facultatively inbreeding complex of six subspecies, each exhibiting different geographic or ecological preferences but with areas of overlap between two or more subspecies in parts of their range. The subspecies form a reticulate pattern of morphologically intergrading populations, some of which are separated only by seemingly minute differences. Other subspecies, were it not for the numerous intermediate plants, appear so dissimilar that some might recognize them as separate species, as has often been done in the past. Five subspecies are in China.

Plants 3-50 cm tall, glabrous or pubescent with short falcate hairs on stem and short glandular hairs in inflorescence. Rhizomes with tuberous thickening at apex. Leaves highly variably shaped from narrowly trullate or elliptic to nearly circular, 1-11 × 0.7-5.5(-8) cm, base narrowly cuneate to cordate, margin subentire to sharply serrate, apex acute to shortly acuminate. Terminal raceme 0.7-2 to 12(-17) cm. Flowering pedicels perpendicular to axis of raceme (in C. alpina subsp. caulescens and some plants of subsp. angustifolia) to ascending or erect, with or without a minute setaceous bracteole at base. Buds glabrous, rarely glabrescent; floral tube ranging from nearly absent to 0.6 mm. Sepals, spreading or slightly reflexed, white or pink, occasionally purple tinged at apex, rarely purple throughout, oblong, ovate to broadly so, or triangular-ovate, 0.8-2 × 0.6-1.3 mm, glabrous, apex rounded to obtuse or miutely mammiform. Petals white, narrowly obtriangular, obdeltoid, obovate to broadly so to depressed-obovate, 0.5-2 × 0.6-1.9 mm, apical notch essentially lacking or to 1/2 length of petal; petal lobes rounded to truncate, rarely somewhat crenulate (in C. alpina subsp. an gustifolia). Stamens erect or ascending, less commonly spreading, equaling or slightly longer than style; nectary wholly within floral tube and inconspicuous. Fruiting pedicel and mature fruit 3.5-7.8 mm. Fruit clavate or obovoid, 1.6-2.7 × 0.5-1.2 mm, tapering smoothly to pedicel, locule 1, seed 1, without ribs or sulci, but pedicel extending as a shallow groove along upper surface. 2n = 22 (unknown in C. alpina subsp. micrantha).

Anhui, Gansu, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Jiangxi, Jilin, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [NE Afghanistan, Bhutan, India, Japan, Kazakhstan, Korea, Mongolia, N Myanmar, Nepal, Russia, Thailand, NW Vietnam; circumboreal in forests between 30°-65° N, but restricted to high elevations at lower latitudes].

Forests, thickets, grassy alpine areas, cool, moist, and wet places, on moss-covered rocks and logs; near sea level to 5000 m.

Circaea alpina, commonly called alpine enchanter's nightshade or small enchanter's nightshade, is a 10–30 cm tall perennial herb found in cool forests of the Northern Hemisphere.