Flora of North America species comparison

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Prunus spinosa

Prunus dulcis

blackthorn, blackthorn plum, sloe, sloe cherry

almond, almond tree, amandier, sweet almond
Habit Shrubs, suckering, 10–40 dm, thorny. Trees, not suckering, 50–80 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.

deciduous;

petiole (8–)10–25 mm, usually winged distally, glabrous, usually glandular distally or on margins at bases of blades;

blade oblong to lanceolate, 2.5–10 × 1–3 cm, base obtuse, margins crenulate-serrulate to crenate-serrate, teeth blunt, glandular, apex acuminate, surfaces glabrous.
Inflorescences

usually solitary flowers, sometimes 2-flowered fascicles.

solitary flowers or 2-flowered fascicles.
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, 4–7 mm, glabrous externally;

sepals erect-spreading to spreading, oblong-ovate, 4–8 mm, margins entire, tomentose, surfaces glabrous;

petals pink to nearly white, obovate, elliptic, or suborbiculate, 12–25 mm;

ovaries hairy.
Drupes

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

mesocarps fleshy;

stones subglobose, ± flattened.

gray-green, ovoid-oblong, compressed, 25–40 mm, velutinous;

mesocarps leathery (splitting);

stones ellipsoid, strongly flattened, pitted.
2n

= 32.

= 16.

Prunus spinosa

Prunus dulcis
Phenology Flowering Mar–May; fruiting Aug–Sep. Flowering Feb–Mar; fruiting Jul–Sep.
Habitat Roadsides Roadsides, canyons, grasslands
Elevation 0–1000 m (0–3300 ft) 20–500 m (100–1600 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; ID; WA; w Asia; n Africa [Introduced in North America]
[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.)

The United States now dominates world almond production with over 40% of the annual crop, all of it grown in or near the Central Valley of California. The in-shell “nuts” sold in stores are the pits of drupes with the leathery mesocarp removed. Almond is among the earliest blossoming trees and one of the first signs of spring in areas where it is grown.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 9, p. 376. FNA vol. 9, p. 372.
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. 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. spinosa, P. subcordata, P. subhirtella, P. texana, P. tomentosa, P. umbellata, P. virginiana, P. yedoensis
Synonyms Amygdalus dulcis, A. communis, P. amygdalus
Name authority Linnaeus: Sp. Pl. 1: 475. (1753) (Miller) D. A. Webb: Feddes Repert. 74: 24. (1967)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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