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Published In: Species Plantarum 2: 577. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library

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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2. Mentha canadensis L. (corn mint)

M. arvensis L., misapplied

M. arvensis ssp. canadensis (L.) H. Hara

M. arvensis f. glabra (Benth.) S.R. Stewart

M. arvensis f. glabrata (Benth.) S.R. Stewart

M. arvensis ssp. piperascens (Malinv. ex Holmes) H. Hara

M. arvensis var. villosa (Benth.) S.R. Stewart

Pl. 436 i; Map 1964

Stems 15–80 cm long, glabrous or sparsely to densely hairy with shorter and/or longer, downward curved to spreading hairs, sometimes mostly along the angles. Leaves short-petiolate, the petiole often narrowly winged. Leaf blades 1.5–8(–12.0) cm long, lanceolate to ovate, elliptic or somewhat rhombic, broadly angled to narrowly tapered at the base, tapered to a sharply pointed tip, the margins sharply toothed, sometimes also short-hairy, the surfaces glabrous or sparsely to moderately pubescent with short, loosely appressed hairs. Inflorescences of axillary clusters, the subtending leaves similar in size to other foliage leaves. Flowers almost always perfect. Calyces 2.5–3.2 mm long, glabrous, but often with sessile glands (hairy elsewhere). Corollas 4–7 mm long, white to lavender or pale pink. Nutlets 0.7–1.3 mm long, usually yellowish brown. 2n=96. July–September.

Scattered nearly throughout the state (most commonly in counties along the Missouri and Mississippi Rivers), but apparently absent for the Unglaciated Plains Division and uncommon in the western half of the Ozarks (U.S. [including Alaska]; Canada, Mexico, Asia; introduced widely). Bottomland forests, banks of streams, rivers, and spring branches, banks of ponds, marshes, fens, marshes, and bases of bluffs; also pastures, railroads, roadsides, and moist, disturbed areas; sometimes emergent aquatics.

Mentha canadensis is the natural source of menthol, an important ingredient in cough drops, candies, chewing gums, tooth pastes, shaving products, perfumes, and mentholated cigarettes, among other uses. The species also is used medicinally. Currently, India and China are the main producers of menthol, but synthetic production also accounts for a significant share of the market (Hopp and Lawrence, 2007).

Mentha arvensis and its allies comprise a circumboreal polyploid complex within which a number of taxa have been recognized as species, subspecies, forms, and hybrids (Harley and Brighton, 1977; Tucker and Chambers, 2002; Tucker and Naczi, 2007). Tucker and Chambers (2002) performed artificial crosses between selected taxa and analyzed the cytology, phytochemistry, and morphology of the resulting hybrids. They determined that North American and Asian populations previously attributed to M. arvensis most likely represent an ancient, stabilized hybrid between the Old World native diploid (2n=24) species, M. longifolia, and a hexaploid (2n=76) population of the European M. arvensis in the strict sense. They resurrected the Linnaean name M. canadensis for this octoploid species. The American/Asian plants are the source of menthol, whereas the related compound, pulegone, is the main ingredient in the essential oils in most of the nine chemotypes of the European taxon (Tucker and Chambers, 2002), which tends to emit a lavender-like fragrance from the crushed foliage. Morphologically, true M. arvensis differs from M. canadensis relatively subtly. According to Gleason and Cronquist (1991) and Tucker and Naczi (2007), M. arvensis has less robust, less strongly ascending stems and ovate to nearly circular leaf blades relatively uniform in size along the stem (vs. progressively smaller toward the stem tip), those subtending flower clusters tending to have more broadly rounded bases. However, Tucker and Chambers (2002) noted that there was some overlap between the two taxa for the leaf characters that they studied. Gleason and Cronquist (1991) further noted that the European taxon is introduced in some northeastern states and provinces (but not Missouri), with intermediates fairly common in the region in which both taxa grow.

Mentha ×gracilis Sole (2n=54, 60, 72, 84, 96, 108, 120) (Pl. 436 g, h) represents a morphologically variable series of sterile hybrids between M. arvensis and M. spicata. In most of the earlier botanical literature, these have been called Mentha ×gentilis L. (which was based on a male-sterile clone of M. arvensis rather than a hybrid) or M. ×cardiaca J. Gerard ex Baker (a later name for M. ×gracilis) (Tucker and Fairbrothers, 1990; Tucker et al., 1991; Tucker and Naczi, 2007). Two independently derived clones within this hybrid complex known as American spearmint and Scotch spearmint are commercial sources of spearmint (Tucker and Fairbrothers, 1990; Tucker et al., 1991), although the parental taxon, M. spicata, also is an important source of this compound. See the treatment of that species for further discussion of spearmint. Mentha ×gracilis currently is known from six counties widely scattered in the state. It is spread vegetatively and commonly found in disturbed habitats such as ditches, railroads, and roadsides, but it also has been reported from banks of streams and fens.



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