Betulaceae

Betulaceae (Birch Family)

http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID

=191 • red alder Betulaceae Alnus rubra • Leaf: Alternate, simple, deciduous, ovate, 3 to 6 inches long, prominently

penniveined leaf with doubly serrate margins that are tightly rolled under at the edges (revolute); petiole 1 inch long and grooved; green to yellow green above and paler green below. Flower: Monoecious; but borne in unisexual aments (catkins), preformed males are slender, pendent, and hang in clusters of 2 to 5; female catkins are short and thick, borne at the ends of branchlets. Fruit: A small semi-woody cone about 1/2 to 1 inch long, persists through the winter, brown, seeds are tiny winged nutlets, shed in the fall. Twig: Young twigs are distinctly triangular in cross-section; olive to reddish brown; prominent lenticels; clearly stalked buds. Bark: Ashy gray to grayish brown, generally smooth but breaking into flat, irregular plates near the base, increasingly covered with white lichens as it ages; inner bark is tan but turns red when exposed to air. Form: A medium sized tree reaching 120 feet tall and 1 to 3 feet in diameter. Typically has a moderately straight bole with an open, broadly pyramidal or dome-shaped crown. Lower trunk is usually free of branches due to intolerance to shade.  

• 377W• Angiosperm

http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID

=12 • yellow birch Betulaceae Betula alleghaniensis • Leaf: Alternate, simple, ovate, 4 to 6 inches long, pinnately-veined, acute tip, rounded

base, doubly serrate margins, somewhat soft or fuzzy, dark green above and paler below. Flower: Monoecious; males are preformed catkins occuring near ends of twig, 1 inch long, reddish green; females are upright 5/8 inches long, reddish green; appear or elongate (males) in the spring. Fruit: Cone like, 3/4 to 1 1/4 inches long, rather plump, upright, with many hairy scales containing 2-winged nutlets, matures in fall and disperse over winter. Twig: Slender, green-brown and hairy when young, light-brown and smooth later; spur shoots present on older trees; buds are ovoid, sharply pointed, reddish brown with ciliate scale margins. Twigs have a wintergreen smell when broken. Bark: On younger stems shiny bronze (sometimes gray), peeling horizontally in thin, curly, papery strips; older trees develop red-brown scaly plates. Form: A medium size tree to 75 feet with an irregular crown.     

• 364E• Angiosperm

http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=11

• sweet birch Betulaceae Betula lenta • Leaf: Alternate, simple, pinnately-veined, ovate, with an acute tip and cordate base,

singly or irregularly doubly, sharply serrate margins, 2 to 4 inches long, petiole is stout and pubescent, dark shiny green above, paler below. Flower: Monoecious; preformed, green male catkins near the end of the twig, 3/4 to 1 inch long; females are upright, 1/2 to 3/4 inch long, green tinged in red, appear or elongate (males) in mid-spring. Fruit: Cone-like aggregate, brown, 1 to 1 1/2 inches long, scales hairless or nearly so, containing very small 2-winged nutlets, ripen and break apart in late summer and fall. Twig: Twigs are slender, reddish brown and lenticellate with a wintergreen smell when cut. On older trees, spur shoots are apparent. Terminal buds are absent, lateral buds two toned, green and brown. Bark: Reddish brown to black on young trees, later gray to nearly black; eventually breaking up into large, thin, irregular, scaly plates. Form: A medium sized tree with a single straight trunk reaching up to 60 feet tall.  

• 365E• Angiosperm

http://dendro.cnre.vt.edu/dendrology/syllabus2/factsheet.cfm?ID=483

• water birch Betulaceae Betula occidentalis • Leaf: Alternate, simple, deciduous, ovate to diamond-shaped, 3/4 to 2

inches long, yellow-green above and initially sticky but becoming smooth, paler and glandular below. Margins distinctly serrated or doubly serrated, except near the base. Flower: Monoecious; with both sexes borne in aments (catkins), male aments preformed and clustered, female aments usually solitary. Fruit: A cylindrical papery strobile (cone) that disintegrates at maturity, 1 inch long, seeds are tiny winged nutlets. Twig: Young twigs are green and sticky, but turn reddish brown and resin-dotted, eventually turn gray-brown and smooth. Bark: Thin and smooth, but dotted with conspicuous lenticles, almost black when young, but turning reddish brown to copper-colored as it ages, older bark may loosen and curl but does not exfoliate. Form: A loosely branched deciduous shrub or small tree growing to 40 feet tall and 1 foot in diameter.     

• 367E 382W• Angiosperm

http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID

=14 • paper birch Betulaceae Betula papyrifera • Leaf: Alternate, simple, pinnately-veined, ovate in shape, 3 to 5 inches long, with

irregularly doubly serrate margins, an acute tip and rounded base (occasionally heart-shaped), green above and paler below. Flower: Monoecious; preformed male catkins near the end of the twig in groups of 2 to 5, 3/4 to 1 1/4 inches long; female are upright, 1 to 1 1/4 inches long, appear or elongate (males) in mid-spring. Fruit: Cone like, cylindrical 1 to 1 1/2 inches long, deciduous at maturity, releasing elliptical 2-winged nutlets, mature in the autumn and disperse over the winter. Twig: Slender, dull red-brown, numerous lighter lenticels, lacking wintergreen smell when cut; terminal bud absent, lateral buds are gummy, green and chestnut brown in color, spur shoots present on older growth. Bark: Reddish brown with light lenticels on very young stems; later turning chalky to creamy white, peeling in horizontal papery strips; brown to black and may be furrowed at base; orange inner bark. Form: A medium sized tree to 70 feet with a pyramidal or irregular crown, often with several trunks.  

• 368E 383W• Angiosperm

http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID

=191 • gray birch Betulaceae Betula populifolia • Leaf: Alternate, simple, pinnately-veined, triangular with a very elongated acuminate

tip, 2 to 3 inches long, doubly serrate margin, green above and paler below. Flower: Monoecious; preformed male catkins near the end of the twig, 3/4 inch long, usually single; female upright, 1/2 inch long; appear or elongate (males) in early spring. Fruit: Cone like, cylindrical, 3/4 inch long, deciduous at maturity, releasing tiny 2-winged nutlets. Matures in autumn, disperses over winter. Twig: Slender, orange-brown to gray in color with warty, raised lenticels that give the twig a rough feel; buds are slender, pointed, green and brown, terminal bud is lacking. Bark: Reddish brown with numerous lighter lenticels on very young stems, later turning gray to white and very chalky; remains smooth and generally does not peel. Form: Small tree rarely over 30 feet tall typically with multiple trunks and a limby bole. The crown is irregular in shape with somewhat drooping slender branches.     

• 370E• Angiosperm

http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID

=17 • American hornbeam Betulaceae Carpinus caroliniana • Leaf: Alternate, simple, elliptical to ovate, 3 to 5 inches long, pinnately veined, tip

acuminate, doubly serrate margin; waxy, smooth green above, paler below. Flower: Monoecious; males a slender, yellow-green hanging catkin, 1 to 2 inches long; female catkins yellow-green and fuzzy appearing from new branch tips, 1/2 to 3/4 inch long, both appearing in mid to late spring. Fruit: Small ribbed nutlet carried on a 3-lobed, slightly folded leafy bract that is 1 inch long (somewhat resembles a maple leaf), bracts are clustered on a long (4 to 6 inches) hanging stalk; ripen in late summer and fall, disperse through the winter. Twig: Slender, somewhat zigzag, brown to gray in color; buds are brown, angled, with a tan silky edge to each scale (making the buds appear lined), approximately 1/4 inch or less in length. Bark: Thin, smooth, gray to bluish gray regardless of age or size; trunk is fluted heavily, resulting in a muscular appearance. Form: A small, nearly shrubby tree reaching up to 25 feet tall with a rounded crown and a twisted trunk.

• 372E• Angiosperm

http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=62

• Eastern hophornbeam Betulaceae Ostrya virginiana • Leaf: Alternate, simple, pinnately veined, oval to broadly lanceolate, 3 to 5 inches

long, with a doubly serrate margin, green above, paler and fuzzy in the axils of veins and on the petiole. Flower: Monoecious; males are preformed catkins, 1/2 to 1 inches long, in clusters of 3's (resemble birds toes), present throughout the winter; females appear in spring and are slender, light green catkins, 1/2 inch long, appearing or elongating (males) in spring. Fruit: Very distinctive, resembling hops. More specifically, a 1/4 inch nutlet is enclosed in a dried, leafy, inflated sac. Serveral sacs hang from one stem, 1 1/2 to 2 1/2 inches long; maturing in late summer and persisting through winter. Twig: Slender, reddish brown, smooth, and may be slightly pubescent. Male catkins present on the end of the branch; buds are small, plump ovate, and covered with green and red-brown, finely grooved (vertically) scales. Bark: When young smooth, reddish brown, with horizontal lenticels (cherry like), later turning light brown and developing a shreddy appearance, broken into small plates or loose scales that are easily broken off with a brush of the hand. Form: A small tree up to 40 feet tall that develops a round crown of fine branches.  

• 374E• Angiosperm