Prunus spinosa |
Prunus mexicana |
|
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blackthorn, blackthorn plum, sloe, sloe cherry |
bigtree plum, Mexican plum |
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Habit | Shrubs, suckering, 10–40 dm, thorny. | Trees, rarely suckering, 30–120 dm, sparsely thorny. |
Twigs | with axillary end buds, hairy. |
with axillary end buds, usually glabrous, sometimes hairy. |
Leaves | deciduous; petiole 4–7 mm, hairy, eglandular; blade elliptic to obovate, 1.5–4 × 1–2.2 cm, base obtuse to rounded, margins crenulate-serrulate, teeth blunt, often glandular, apex acute to obtuse, abaxial surface hairy (especially along midribs and veins), adaxial glabrate. |
deciduous; petiole 4–18 mm, hairy, rarely only adaxially, usually glandular distally, glands 1–2(–4); blade usually elliptic, sometimes broadly elliptic, obovate, ovate, or oblong, 6–12 × 3–7 cm, base usually obtuse to broadly rounded, sometimes subcordate, margins coarsely, doubly serrate, teeth sharp, eglandular, apex usually abruptly acuminate to acuminate, rarely acute, abaxial surface densely hairy, adaxial rugose, glabrous or hairy. |
Inflorescences | usually solitary flowers, sometimes 2-flowered fascicles. |
2–5-flowered, umbellate fascicles. |
Pedicels | 0.5–5(–8) mm, usually glabrous, rarely hairy. |
4–20 mm, usually glabrous, sometimes sparsely hairy. |
Flowers | blooming before leaf emergence; hypanthium cupulate, 1.5–2.5 mm, glabrous externally; sepals spreading, oblong, 1.5–2.5 mm, margins glandular-toothed, surfaces glabrous or adaxially hairy at bases; petals white, elliptic, 4–8 mm; ovaries glabrous. |
blooming before leaf emergence; hypanthium obconic, 2–4.5 mm, glabrous or hairy externally; sepals reflexed, ovate to lanceolate, 1.5–4 mm, margins entire or irregularly or obscurely glandular-toothed, sometimes 2-fid at apices, ciliate, surfaces hairy; petals white, sometimes turning pink, elliptic to obovate, 5–10 mm; ovaries glabrous. |
Drupes | bluish black, globose, 10–15 mm, glabrous; mesocarps fleshy; stones subglobose, ± flattened. |
purplish red to dark blue, glaucous, subglobose to ellipsoid, 15–30 mm, glabrous; mesocarps fleshy; stones ovoid-ellipsoid, strongly flattened. |
2n | = 32. |
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Prunus spinosa |
Prunus mexicana |
|
Phenology | Flowering Mar–May; fruiting Aug–Sep. | Flowering Mar–Apr; fruiting Aug–Oct. |
Habitat | Roadsides | Stream bottoms, open woods, edges of woods |
Elevation | 0–1000 m (0–3300 ft) | 10–400 m (0–1300 ft) |
Distribution |
CT; ID; MA; ME; MI; NY; OR; WA; BC; NS; ON; Eurasia; n Africa [Introduced in North America]
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AL; AR; IA; IL; IN; KS; KY; LA; MO; MS; OK; TN; TX; Mexico (Coahuila, Nuevo León, San Luis Potosí, Tamaulipas)
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Discussion | As past flora writers (C. L. Hitchcock et al. 1955–1969; E. G. Voss 1972–1996) have noted, the distinctions between Prunus spinosa and P. domestica are not clear. Some researchers consider the hexaploid P. domestica to have been derived from the tetraploid P. spinosa, often in a scenario involving hybridization with P. cerasifera. It should not be surprising that some of the characters used in keys to separate these three taxa (spininess, indument, leaf size, pedicel length, numbers of flowers per bud) are subject to variation within each species and overlap among the species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
As L. H. Shinners (1956b) pointed out, plums from Texas determined as Prunus americana var. lanata Sudworth are not P. americana but P. mexicana. This was extrapolated by others to mean that all hairy americana-type plums, which had been called var. lanata, are P. mexicana. As a consequence, P. mexicana is often listed from states far from where it truly occurs (for example, North Carolina, Ohio, Wisconsin) and herbarium sheets of hairy P. americana can often be found filed under P. mexicana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 376. | FNA vol. 9, p. 379. |
Parent taxa | Rosaceae > subfam. Amygdaloideae > tribe Amygdaleae > Prunus | Rosaceae > subfam. Amygdaloideae > tribe Amygdaleae > Prunus |
Sibling taxa | ||
Name authority | Linnaeus: Sp. Pl. 1: 475. (1753) | S. Watson: Proc. Amer. Acad. Arts 17: 353. (1882) |
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