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blackthorn, blackthorn plum, sloe, sloe cherry

Catalina cherry, evergreen cherry, holly leaf cherry, islay

Habit Shrubs, suckering, 10–40 dm, thorny. Shrubs or trees, sometimes suckering, 10–150 dm, not thorny.
Twigs

with axillary end buds, hairy.

with terminal end buds, glabrous.

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.

persistent;

petiole 3–25 mm, glabrous, eglandular;

blade oblong-ovate to ovate-lanceolate or ovate to suborbiculate, 1.6–12 × 1.2–5(–7) cm, base usually broadly rounded to subcordate, sometimes obtuse, margins spinose-dentate to spinose-serrulate or entire, sometimes undulate, teeth sharp, callus-tipped, sometimes glandular at leaf base, apex acute to acuminate, surfaces glabrous, abaxial eglandular, if glands present, restricted to margins.

Inflorescences

usually solitary flowers, sometimes 2-flowered fascicles.

15–40-flowered, racemes;

central axes 30–80 mm, leafless at bases.

Pedicels

0.5–5(–8) mm, usually glabrous, rarely hairy.

1–5 mm, glabrous.

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 cupulate, 2–3 mm, glabrous externally;

sepals erect to spreading, triangular, 0.7–1.2 mm, margins entire, surfaces usually glabrous, rarely with scattered hairs;

petals white to yellowish, elliptic, obovate, or suborbiculate, 1–3 mm;

ovaries glabrous.

Drupes

bluish black, globose, 10–15 mm, glabrous;

mesocarps fleshy;

stones subglobose, ± flattened.

dark red to purple or blue-black, obovoid or ellipsoid to globose, 12–25 mm, glabrous;

mesocarps leathery;

stones subglobose to ellipsoid, ± flattened.

2n

= 32.

Prunus spinosa

Prunus ilicifolia

Phenology Flowering Mar–May; fruiting Aug–Sep.
Habitat Roadsides
Elevation 0–1000 m (0–3300 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
CA; nw Mexico
[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.)

Varieties 2 (2 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Leaf blades ovate to suborbiculate, margins spinose-dentate to spinose-serrulate; petioles 3–10 mm.
var. ilicifolia
1. Leaf blades oblong-ovate to ovate-lanceolate, margins usually entire, sometimes remotely spinose-serrulate; petioles 8–25 mm.
var. occidentalis
Source FNA vol. 9, p. 376. FNA vol. 9, p. 362.
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. 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. spinosa, P. subcordata, P. subhirtella, P. texana, P. tomentosa, P. umbellata, P. virginiana, P. yedoensis
Subordinate taxa
P. ilicifolia var. ilicifolia, P. ilicifolia var. occidentalis
Synonyms Cerasus ilicifolia
Name authority Linnaeus: Sp. Pl. 1: 475. (1753) (Nuttall ex Hooker & Arnott) D. Dietrich: Syn. Pl. 3: 43. (1842)
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