| TREATMENT FROM THE JEPSON MANUAL (1993) |
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©Copyright 1993 by the Regents of the University of California
For up-to-date information about California vascular plants, visit the Jepson eFlora. |
AND IS MAINTAINED FOR ARCHIVAL PURPOSES ONLY |
Tree, shrub, monoecious
Stem: trunk < 35 m; bark ± smooth; lenticels present
Leaves simple, alternate, petioled, deciduous; stipules deciduous; blade ovate to elliptic, generally serrate, ± doubly so
Inflorescence: catkin, generally appearing before leaves, often clustered; bracts each subtending 2–3 flowers and 3–6 bractlets
Staminate inflorescence pendent, ± elongate
Pistillate inflorescence pendent or erect, developing variously in fruit (see key to genera)
Staminate flower: sepals 0–4, minute; petals 0; stamens 1–10; pistil vestigial or 0
Pistillate flower: sepals 0–4; petals 0; stamens 0; pistil 1, ovary inferior, chambers 2, each 1-ovuled, stigmas 2
Fruit: nut or nutlet, sometimes winged, subtended or enclosed by 1–2 bracts
Genera in family: 6 genera, 105 species: generally n hemisphere; some cultivated.
Tree, shrub
Stem: trunk < 30 m; bark smooth or scaly, aromatic, often peeling in thin layers; twigs puberulent, glandular, or both; lenticels prominent; winter buds sessile, 3-scaled
Leaf glandular-hairy; blade 2–5 cm, widely elliptic, base ± truncate to tapered
Staminate inflorescence 2–7 cm; bracts each subtending 3 flowers and 3 bractlets
Pistillate inflorescence 2–3 cm; bracts each subtending 3 flowers and 3 bractlets
Staminate flower: sepals 4; stamens 2
Pistillate flower: sepals 0
Fruits many, in a non-cone-like catkin, winged; bracts lobed, papery, released with but not attached to fruit
Species in genus: 50 species: circumboreal
Etymology: (Latin: birch)
Important wildlife food; wood used for interior finishing; many species cultivated.