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Published In: Gray's Manual of Botany (ed. 7) 707. 1908. (Manual (ed. 7)) Name publication detail

Project Name Data (Last Modified On 8/25/2017)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Native


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6. Pycnanthemum virginianum (L.) B.L. Rob. & Fernald (Virginia mountain mint)

Pl. 440 i, j; Map 1987

Stems 40–90(–120) cm long, moderately to densely and evenly pubescent on the angles or nearly so, the angles with mostly short, curled hairs, the sides glabrous or rarely with a few hairs. Leaves sessile. Leaf blades 2–6 cm long, 5–11 mm wide, lanceolate to linear-lanceolate, angled or short-tapered at the base, the margins entire or rarely with a few teeth, the surfaces glabrous or more commonly the undersurface sparsely short-hairy along the midvein, green. Inflorescences relatively dense, often appearing relatively flat-topped, only the lowermost branches observable. Bracts similar to the foliage leaves, not whitened, green, glabrous or sparsely short-hairy on the upper surface. Bractlets 2–4 mm long, lanceolate to narrowly ovate, lacking a thickened midvein, densely short-hairy toward the sharply pointed but nonspinescent tip. Calyces 3–5 mm long, actinomorphic or nearly so, densely pubescent, mostly above the midpoint, with short, curled hairs, the lobes all similar in size, 0.5–1.0 mm long, triangular, sharply pointed, lacking a sharply pointed extension of the midnerve. Corollas 4.0–6.5 mm long, white to pale pinkish-tinged or pale lavender. Nutlets 1.0–2.2 mm long, glabrous. 2n=80. July–October.

Scattered, mostly in the Ozark and Ozark Border Divisions, uncommon in other parts of the state (eastern U.S. west to North Dakota, Colorado, and Oklahoma; Canada). Banks of streams, rivers, and spring branches, ledges of bluffs, fens, swamps, bottomland prairies, uplands prairies, and occasionally glades; also railroads; commonly on calcareous substrates.

E. Grant and Epling (1943) reported scattered specimens with foliage similar to that of P. pilosum but infloresacences more similar to those of P. virginianum that they interpreted as putative hybrids between the two species. For a discussion of uncommon specimens resembling P. virginianum but with stems having somewhat denser hairs on the sides, see the treatment of P. torreyi.



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