8. Galium divaricatum Pourr. ex Lam. (Lamarck’s bedstraw)

Pl. 548 a, b; Map 2542

Plants annual, sometimes becoming slightly hardened at the base at maturity. Stems 10–40 cm long, usually weak,erect to loosely ascending or clambering, often branched or tufted, roughened with minute, prickly, downward-angled hairs on the angles, otherwise glabrous. Leaves (2)4–6(–8) per node, spreading or downward-angled in orientation. Leaf blades 2–6 mm long, 0.5–2.0 mm wide, narrowly elliptic to narrowly oblong or linear, angled or short-tapered to a sharply pointed tip, the midvein sometimes extended into a minute, sharp point, angled to truncate at the base, not glandular on the undersurface, glabrous, with only the midvein visible, the margins with minute, stiff, prickly hairs and usually curled under. Inflorescences terminal and also axillary from the uppermost leaves, the axillary ones not pendant, positioned over the leaves, consisting of small clusters or fascicles, these usually grouped into small panicles with mostly 3–6 branch points and relatively short, loosely ascending to spreading branches. Flowers relatively few, the stalks 0.5–2.0 mm long. Corollas 0.4–0.6 mm long, 4-lobed, white. Fruits about 1 mm long, 1.5 mm wide, the surface glabrous, smooth to granular. 2n=22, 44. May–June.

Introduced, uncommon, known thus far only from Henry and Oregon Counties (native of Europe; introduced widely but sporadically in the U.S.). Cemeteries and railroads.

This species was first reported for Missouri by Castaner (1982a). Its taxonomy was clarified by Lipscomb and Nesom (2007), who redetermined a number of collections from the eastern United States as either G. anglicum Hudson or G. parisiense L. (the latter not yet known from Missouri). Galium divaricatum is similar to Galium parisiense L., which differs in its fruits that are densely covered with spreading, hooked hairs; also G. parisiense is usually a taller, rather leggier plant. The two species have mistakenly been combined in some herbaria and literature, with G. divaricatum at times mistakenly equated with a smooth-fruited European variant of G. parisiense, G. parisiense var. leiocarpum Tausch.

The mericarps of the fruits are relatively elongated and curved, that is rather sausage-shaped, and as they mature they grow apart until they are not even touching, with each of them connected separately to the stalk.