Alnus oblongifolia
Alnus rubra
aliso (Mexico), Arizona alder, New Mexican alder, oblong leaf alder
Oregon alder, red alder
dark gray, smooth, becoming blackish and breaking into shallow vertical plates in age;
lenticels inconspicuous.
gray, smooth, darkening and breaking into shallow rectangular plates in age;
lenticels inconspicuous.
blade narrowly ovate or lanceolate to narrowly elliptic, 5–9 × 3–6 cm, leathery, base narrowly to broadly cuneate or narrowly rounded, margins flat, sharply and coarsely doubly serrate, rarely evenly and densely short-serrate, major teeth sharp, acuminate, secondary teeth distinctly larger, apex long to short-acuminate, rarely acute;
surfaces abaxially glabrous to sparsely pubescent or infrequently villous, moderately resin-coated.
blade ovate to elliptic, 6–16 × 3–11 cm, leathery, base broadly cuneate to rounded, margins strongly revolute, deeply doubly serrate or crenate, with distinctly larger secondary teeth, apex acute to obtuse;
surfaces abaxially glabrous to sparsely pubescent.
formed season before flowering and exposed during winter; staminate catkins in 1 or more clusters of 3–6, 3.5–10 cm; pistillate catkins in 1 or more clusters of 2–7.
formed season before flowering and exposed during winter; staminate catkins in 1 or more clusters of 2–6, 3.5–14 cm; sistillate catkins in 1 or more clusters of 3–8.
ovoid, ellipsoid, or nearly cylindric, 1–2.5 × 0.8–1.5 cm;
peduncles 5–10 mm.
ovoid to nearly globose, 1–3.5 × 0.6–1.5 cm;
peduncles 1–10 mm.
buds stipitate, ovoid, 4–8 mm, apex rounded;
stalks 1.5–4 mm;
scales 2, equal, valvate, sometimes incompletely covering underlying leaves, moderately resin-coated.
buds stipitate, ellipsoid, 6–10 mm, apex rounded, long;
stalks 2–8 mm;
scales 2–3, outer 2 equal and valvate, usually heavily resin-coated.
before new growth in spring.
before new growth in spring.
elliptic to obovate, wings narrower than body, irregular in shape, leathery.
ovate or elliptic, wings much narrower than body, irregularly elliptic to obovate, leathery.
= 28.
Alnus oblongifolia
Alnus rubra
Alnus oblongifolia is closely related to the Mexican and Central American A. acuminata, with which it has sometimes been confused. It is found only in scattered populations in the temperate deciduous forest vegetation zone of high mountains in the arid Southwest.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Alnus rubra is the largest alder in North America north of Mexico; it often forms extensive stands along streams and on low-lying flood plains in the Pacific Northwest. The strongly revolute margins of its leaf blades make it easily distinguished from all of the other alders in the flora. It is an important commercial tree; the wood is used to make inexpensive furniture, small wooden items, and paper pulp.
Native Americans used various parts of plants of Alnus rubra medicinally as a purgative, an emetic, for aching bones, headaches, coughs, biliousness, stomach problems, scrofula sores, tuberculosis, asthma, and eczema, and as a general panacea (D. E. Moerman 1986).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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