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Published In: Hortus Kewensis; or, a catalogue . . . 1: 145. 1789. (Hort. Kew.) Name publication detailView in BotanicusView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 9/8/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status : Native

 

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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.

 


 

 
 
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