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Viburnum
See list of 13 species in this genusSpecies with 3-lobed leaf blades often will produce unlobed blades at the apex of shoot growth. Therefore, these leaves should not be used for identification purposes. Reference: McAtee (1956).
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1a. Leaf blades 3-lobed (sometimes the most apical pair of the shoot with simple blades) [Fig. 314]
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2a. Bud scales 3 or more, generally at least sparsely pubescent; branchlets pubescent with stellate hairs; petioles lacking glands; drupe dark blue to dark purple
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2b. Bud scales 2 (sometimes appearing as 1), glabrous; branchlets glabrous or stipitate-glandular, not stellate-pubescent; petioles with raised glands; drupe red
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3a. Marginal flowers of inflorescence not enlarged, fertile, similar in morphology to other flowers in the inflorescence; leaves without stipules, the blades usually toothed in the sinuses; petiole glands usually at very summit near edge of leaf blade; winter buds dark purple
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3b. Marginal flowers of inflorescence enlarged and neutral; leaves with slender stipules, the blades usually lacking teeth in the sinuses; petiole glands usually near apex of petiole but separated a short distance from the blade; winter buds red
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4a. Winter buds naked [Fig. 312]; branchlets, winter buds, leaves, and inflorescence axes stellate-pubescent; drupes red (eventually turning very dark)
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5a. Marginal flowers of inflorescence not enlarged, fertile, similar in morphology to other flowers in the inflorescence; leaf blades 5–12 cm long; pubescence gray; stems erect
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5b. Marginal flowers of inflorescence enlarged and sterile; leaf blades 10–18 cm long; pubescence yellow-brown to red-brown; stems straggling or loosely ascending
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4b. Winter buds perulate; stellate hairs absent or present and then generally restricted to the leaves (abundant in V. plicatum, also on the winter buds in V. sieboldii); drupes dark blue to dark purple (red in V. dilatatum, at first pink in V. sieboldii)
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6a. Leaf blades with prominent, subpalmate or pinnate, simple to twice-forked (infrequently thrice-forked) veins that extend to the tip of each tooth; winter buds with 2 or 4 visible scales
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7a. Inflorescence a panicle, with opposite branches; leaf blades elliptic-obovate, cuneate at the base, with a strong smell of green pepper when bruised
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7b. Inflorescence an umbel-like cyme, with whorled lower branches; leaf blades narrow-ovate or ovate to oblong-ovate or suborbicular, rounded to cordate at the base (rarely broad-cuneate), without a strong smell when bruised
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8a. Winter buds with 2 visible, valvate outer scales
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9a. Winter buds scurfy-pubescent; flowers all fertile, ca. 5 mm in diameter; leaf blades abaxially appressed-pubescent; drupe red at maturity
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9b. Winter buds stellate-pubescent; usually all the flowers of cyme enlarged, 15–30 mm in diameter, and sterile; leaf blades abaxially glabrate to sparsely appressed-pubescent; drupe at first red, turning blue-black (but this rarely produced in New England populations)
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8b. Winter buds with 4 visible scales, the outer imbricate, the inner valvate
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10a. Leaves stipulate, with petioles 2–15 mm long [Fig. 315]; stylopodium pubescent; stone of drupe compressed
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10b. Leaves exstipulate, with petioles 8–25 mm long; stylopodium glabrous; stone of drupe plump
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6b. Leaf blades with many-forked, less conspicuous, pinnate veins that anastomose near the margin and do not extend to the tip of each tooth; winter buds with 2 visible, valvate scales
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11b. Cymes sessile or rarely slightly elevated on peduncles up to 5 mm long; leaf blades serrulate; outer bud scales not ribbed, upon bud expansion either soon detaching or slightly expanding but not long persistent
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12a. Some leaf blades acuminate at apex; petioles 10–20 (–35) mm long, with an undulate- or denticulate-margined wing
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12b. Leaf blades acute to obtuse at apex; petioles 5–12 mm long, without or with an obscure wing margin
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Each photo represents one species in this genus.