Galium virgatum Nutt. ex Torr. & A. Gray

Southwestern Bedstraw


CC = 4
CW = 5
MOC = 41

© SRTurner

Family - Rubiaceae

Habit - Annual forb.

Stems - To 30 cm, ascending to erect, square in cross section, angles with sparse, stiff hairs, faces glabrous.

Galium_virgatum_stem.jpg Stems.

© SRTurner

Galium_virgatum_stem2.jpg Stem and node.

© SRTurner

Leaves - Whorled with 4-5 per node, sometimes appearing more due to additional axillary leaves, leaf whorl usually somewhat asymmetric. Blades sessile, to 7 mm long, narrowly elliptic or lanceolate, pointed at tips, angled at base, with single midvein, undersurface with round to linear impressed glands appearing as dots or lines. Margins entire, flat, ciliate.

Galium_virgatum_leaves.jpg Leaves abaxial.

© SRTurner

Flowers - Borne singly in upper leaf axils, pendent and mostly hidden underneath the leaves, nearly sessile. Calyces minute or absent. Corollas 0.5 mm, 4-lobed, cream colored. Stamens 4, with anthers exserted. Style 2-lobed, with 2 capitate stigmas. Ovary inferior, 2-locular, with 1 ovule per locule.

Galium_virgatum_flowers.jpg Flowers.

© SRTurner

Fruits - Ovoid to subglobose schizocarps, 2-lobed, about 2 mm in diameter, densely pubescent with hooked hairs.

Galium_virgatum_fruit.jpg Fruits.

© SRTurner

Flowering - April - June.

Habitat - Glades, rocky upland prairies, ledges, bluff tops.

Origin - Native to the south-central U.S.

Lookalikes - G. pedemontanum.

Other info. - This plant is very small and easily missed. Among the Missouri species of Galium, it can often be recognized at a glance by habitat and the asymmetric arrangement of the leaf whorls. The flowers are minute and usually not seen except by close examination. The plant is mostly found in the southern half of the state. Beyond Missouri its range extends to Oklahoma, Arkansas, and Texas, with scattered populations in a few other states.

This species can be confused with Galium pedemontanum, which is superficially similar. In that species, the fruits and ovaries lack hooked hairs. The two are very different in their habitat preferences.

Photographs taken at St. Joe State Park, St. Francois County, MO, 5-13-2016, and at Shaw Nature Reserve, Franklin County, MO, 5-26-2021 (SRTurner).