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blackthorn, blackthorn plum, sloe, sloe cherry

bigtree plum, Mexican plum

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.

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
from FNA
CT; ID; MA; ME; MI; NY; OR; WA; BC; NS; ON; Eurasia; n Africa [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; IA; IL; IN; KS; KY; LA; MO; MS; OK; TN; TX; Mexico (Coahuila, Nuevo León, San Luis Potosí, Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
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
P. americana, P. andersonii, P. angustifolia, P. armeniaca, P. avium, P. caroliniana, P. cerasifera, P. cerasus, P. domestica, P. dulcis, P. emarginata, P. eremophila, P. fasciculata, P. fremontii, P. geniculata, P. glandulosa, P. gracilis, P. havardii, P. hortulana, P. ilicifolia, P. laurocerasus, P. lusitanica, P. mahaleb, P. maritima, P. mexicana, P. minutiflora, P. murrayana, P. myrtifolia, P. nigra, P. padus, P. pensylvanica, P. persica, P. pumila, P. rivularis, P. serotina, P. speciosa, P. subcordata, P. subhirtella, P. texana, P. tomentosa, P. umbellata, P. virginiana, P. yedoensis
P. americana, P. andersonii, P. angustifolia, P. armeniaca, P. avium, P. caroliniana, P. cerasifera, P. cerasus, P. domestica, P. dulcis, P. emarginata, P. eremophila, P. fasciculata, P. fremontii, P. geniculata, P. glandulosa, P. gracilis, P. havardii, P. hortulana, P. ilicifolia, P. laurocerasus, P. lusitanica, P. mahaleb, P. maritima, P. minutiflora, P. murrayana, P. myrtifolia, P. nigra, P. padus, P. pensylvanica, P. persica, P. pumila, P. rivularis, P. serotina, P. speciosa, P. spinosa, P. subcordata, P. subhirtella, P. texana, P. tomentosa, P. umbellata, P. virginiana, P. yedoensis
Name authority Linnaeus: Sp. Pl. 1: 475. (1753) S. Watson: Proc. Amer. Acad. Arts 17: 353. (1882)
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