11. Galium pilosum Aiton (hairy bedstraw)
G. pilosum var. puncticulosum (Michx.) Torr.
& A. Gray
Pl. 548 e–g; Map
2545
Plants
perennial. Stems 20–80 cm long, variously erect to loosely ascending, sometimes
weak and spreading or reclining, unbranched or few- to several-branched from
the base, rarely also with few branches toward the tip, moderately to densely
pubescent with fine, straight or curved, soft, more or less spreading hairs
(rarely those toward the stem base upwardly incurved), rarely glabrous or
nearly so. Leaves 4 per node, spreading in orientation. Leaf blades 5–25 mm
long, 2–14 mm wide, elliptic to oblong-elliptic or narrowly oval, rounded or
more commonly angled to a usually bluntly pointed tip, the midvein occasionally
extended into a minute, sharp point (especially on smaller leaves), angled at
the base, the undersurface with minute, impressed, linear to oblong or circular
glands (appearing as small dots, streaks, and/or lines), otherwise sparsely to
moderately pubescent with short, fine, straight to curved hairs along and often
also between the veins, the venation palmate with 3 veins (the midvein and 2
finer lateral veins, these sometimes obscure or produced only toward the blade
base) visible, the margins with fine, soft hairs, flat or only slightly curled
under. Inflorescences terminal and usually also axillary from the upper leaves,
not pendant, positioned over the leaves, consisting of small panicles (1–4 cm
long) with mostly 1–3 branch points or reduced and appearing as unbranched
racemes, the branches short to relatively long, spreading to ascending. Flowers
relatively few to more commonly several to numerous, the stalks 1–3 mm long
(becoming elongated to 4–10 mm at fruiting). Corollas 1.0–1.5 mm long, 4-lobed,
dark purple or maroon. Fruits 2.0–2.5 mm long, 2.5–3.5 mm wide, the surface
densely pubescent with short (ca. 1 mm long), hooked hairs. 2n=22.
June–August.
Scattered, mostly
south of the Missouri River (eastern U.S. west to Kansas and New Mexico;
Canada). Mesic to dry upland forests, bases and ledges of bluffs, savannas,
edges of glades, upland prairies, sand prairies, banks of streams and rivers,
and margins of ponds and lakes; also old quarries, railroads, and roadsides.
Two varieties of
Galium pilosum have sometimes been recognized, var. pilosum and
var. puncticulosum (Steyermark, 1963). These are separated only by the
density, length, and orientation of the stem hairs, and they intergrade widely.
Steyermark noted that although both varieties grow in Missouri, plants
assignable to var. puncticulosum are very rarely encountered nearly
throughout the range of var. pilosum in the state. The taxonomic
recognition of only the two extremes of a continuous range of morphological
variation does not seem informative and is not done here.
Occasional
specimens of G. pilosum from throughout its range (including Missouri)
are malformed by an undetermined pathogen, such that their inflorescences are
enlarged, with groups of small leaves or bracts and apparently numerous
flowers. The identification of such plants may be problematic if their abnormal
development is not recognized.