15. Galium virgatum Nutt. ex Torr. & A. Gray (southwestern bedstraw)
Pl. 548 j, k;
Map 2549
Plants annual.
Stems 8–20(–40) cm long, erect or ascending, sometimes from a spreading base,
with minute, prickly, more or less spreading hairs on the angles, otherwise
usually glabrous. Leaves 4 per node (but sometimes apparently more because of
short axillary stems with additional leaves), mostly ascending in orientation.
Leaf blades 2–7 mm long, 1–2 mm wide, narrowly elliptic to lanceolate,
occasionally the smaller ones elliptic, angled to a bluntly or sharply pointed
tip, the midvein sometimes extended into a minute, sharp point, rounded or
angled at the base, the undersurface with impressed, round to linear glands
(appearing as faint, irregular dots, streaks, and/or lines), otherwise glabrous
or with sparse, stiff hairs along the midvein, the margins flat, pubescent with
relatively long, stiff, spreading to more commonly ascending hairs.
Inflorescences axillary from all but the lowermost leaves, pendant, hanging
below and largely covered by the leaves, consisting of solitary flowers.
Flowers subsessile, the stalks 0.3–0.8 mm long. Corollas 0.4–0.6 mm long,
4-lobed, pale yellow or cream-colored. Fruits 1.5–2.0 mm long, 2–3 mm wide, the
surface densely pubescent with hooked hairs to 1 mm long. April–June.
Scattered in the
Ozark, Ozark Border, and Unglaciated Plains Divisions, north locally to Lincoln
County (Illinois to Alabama west to Kansas and Texas). Glades, ledges and tops
of bluffs, and rocky portions of upland prairies; rarely also gardens and
roadsides.
Steyermark
(1963) reported that the species dries up and disappears by midsummer. In
Missouri, the native G. virgatum sometimes has been confused with the
superficially similar, nonnative taxon, G. pedemontanum. That species
differs in its clusters of mostly two or three flowers, as well as fruits and
ovaries lacking hooked hairs. Also, plants of G. virgatum are mostly
encountered as single-stemmed individuals, whereas those of G. pedemontanum
are mostly several stemmed and strongly colonial.