57. Galium tricornutum Dandy, Watsonia. 4: 47. 1957.
麦仁珠 mai ren zhu
Herbs, annual, weakly ascending to procumbent or clambering. Stems 5-80 cm tall, 4-angled, often little branched, glabrescent, densely retrorsely aculeolate on angles. Leaves in whorls of 6-8, subsessile; blade drying papery, narrowly oblanceolate to narrowly elliptic, 10-32 × 2-6 mm, glabrescent, upper side glabrous, lower side densely aculeolate along midrib, base acute, margins densely retrorsely and antrorsely aculeolate, apex acute; vein 1. Inflorescences elongated thyrsoid, cymes terminal and axillary on short lateral stems, mostly 3-5-flowered; axes retrorsely aculeolate; bracts none or leaflike and 3-5 mm; pedicels 0.3-2 mm. Ovary ellipsoid to didymous, 0.3-0.5 mm, smooth to verrucose or spinulose. Corolla white, rotate, 1-1.5 mm in diam., lobed for 2/3 or more; lobes triangular. Mericarps subglobose, ca. 3 × 4-6 mm, becoming verrucose to tuberculate but never with uncinate trichomes, pendulous on arching pedicels to 7 mm. Fl. Apr-Jun, fr. May-Mar.
Adventive weeds in meadows on mountain slopes, open fields, river beaches, ditch sides; 400-4000 m. Anhui, Gansu, Guizhou, Henan, Hubei, Jiangsu, Jiangxi, Shaanxi, Shanghai, Shanxi, Sichuan, Xinjiang, Xizang [India, Pakistan; N Africa, SW Asia, Europe, North America].
In general aspect and habit the weedy annual Galium tricornutum from G. sect. Kolgyda strongly resembles G. spurium and G. aparine but can be separated by its above glabrous leaves and its verrucose fruit on arching pedicels. Galium tricornutum apparently is rare in China. The above wide distribution data from FRPS evidently is due to misidentifications of the common G. spurium.
Galium tricornutum has long been treated under the illegitimate superfluous name G. tricorne Stokes, published in 1787. Stokes’s intent was to transfer Valantia aparine Linnaeus (= G. verrucosum Hudson, 1767) to Galium, where the epithet "aparine" was blocked by G. aparine Linnaeus. The specimens on which Stokes based his name belonged partly to G. verrucosum and partly to G. tricornutum, two close but very well-separated species. However, when Stokes published his article, the previously and validly published name in Galium by Hudson (1767) already existed and made his name superfluous. That remained unnoticed and G. tricorne was generally used for our species. Only in 1975 did Dandy clarify this situation, designating G. tricornutum as the new name for the long known but misnamed G. tricorne.