Prunus maritima
Prunus nigra
beach plum
black plum, Canada plum, Canadian plum, prunier noir
with axillary end buds, densely hairy to glabrate.
with axillary end buds, usually glabrous, rarely hairy.
deciduous;
petiole 3–11 mm, usually densely hairy, rarely hairy only on adaxial surface, usually eglandular, sometimes glandular distally, glands 1–2, discoid;
blade elliptic, broadly elliptic, or obovate (orbiculate in gravesii clone), 3.5–7 × 2–4 cm, base cuneate to obtuse (rounded in gravesii clone), margins finely, usually singly, rarely doubly, serrulate, teeth sharp, usually eglandular, rarely glandular, apex acute to obtuse (rounded in gravesii clone), abaxial surface usually hairy, sometimes only on veins or glabrescent, adaxial rugose, glabrous.
deciduous;
petiole 8–22 mm, glabrate with hairs adaxially, sometimes glandular distally, glands 1–3, discoid;
blade broadly elliptic to obovate, (5–)7–11 × 3–6.5 cm, base obtuse to rounded or subcordate, margins doubly crenate-serrate, teeth blunt, glandular, apex abruptly acuminate, abaxial surface hairy along midribs and major veins, adaxial glabrous.
2–4-flowered, umbellate fascicles.
2–4-flowered, umbellate fascicles.
5–15 mm, hairy.
7–20 mm, usually glabrous, rarely hairy.
blooming before leaf emergence;
hypanthium campanulate, 2.5–3.5 mm, hairy externally;
sepals erect to spreading, ovate, 1.5–3.5 mm, margins entire, sometimes 2-fid at apices, ciliate, surfaces hairy;
petals white, oblong-obovate, 3–8 mm;
ovaries glabrous.
blooming before or at leaf emergence;
hypanthium red-tinged, obconic, 3–4(–5) mm, usually glabrous, rarely hairy externally;
sepals broadly spreading to reflexed, ovate, 2–4(–5) mm, margins glandular-toothed, abaxial surface usually glabrous, rarely sparsely hairy, adaxial glabrous or hairy;
petals white, often fading to pink, suborbiculate to oblong-obovate, 8–13 mm;
ovaries glabrous.
red, yellow, dark blue, or purplish black, glaucous, globose, 11–18 mm, glabrous;
mesocarps fleshy;
stones ovoid, slightly flattened.
red, orange, or yellowish, barely glaucous, globose to ellipsoid, 15–30 mm, glabrous;
mesocarps fleshy;
stones ovoid-ellipsoid, strongly flattened.
= 16.
= 16.
Prunus maritima
Prunus nigra
Prunus gravesii has been known from only a single locality since its description in 1897, and there may never have been more than a single, multistemmed individual. G. J. Anderson (1980) concluded that it is a mutant derivative of P. maritima. In the study by Anderson, it differed with statistical significance from other specimens of P. maritima for only 4 of 38 morphological features measured, and even for those four the range in values between the two taxa overlapped. Their leaf flavonoid chromatograms were identical. From a conservation standpoint it is of value to designate the orbiculate-leaved gravesii clone as a distinct taxonomic variety, for which the name P. maritima var. gravesii (Small) G. J. Anderson is available. Once listed by the state of Connecticut as endangered, it is now believed to be extinct in the wild. Throughout much of its original range P. maritima is threatened by oceanside development.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
In the northeastern United States and adjacent Canada, Prunus nigra co-occurs with, and is sometimes confused with, P. americana, despite being distinct in both flower and leaf. The red-tinged hypanthia and sepals of P. nigra give the entire inflorescence a pinkish coloration even when the petals are pure white, and the sepals bear obvious glandular teeth along their margins; in P. americana the hypanthia and sepals are green and the sepals bear relatively few glandular teeth or are eglandular. The leaf marginal teeth of P. nigra are rounded and bear glands at their tips or have callus scars where the glands fell off; those of P. americana are acute and eglandular; some may have a callused tip.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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