United States
Department of
Agriculture
Forest Service
Rocky Mountain
Research Station
Ft. Collins, CO
General Technical Report
RMRS-GTR-118-CD
February 2004
| Authors |
| Acknowledgments |
| Introduction |
| Species description format |
| Trees |
| Shrubs |
| Ferns & Friends |
| Forbs |
| Graminoids |
| Descriptive drawings |
| Collecting and pressing methods |
| Glossary |
| References |
Key to Alnus Species
1. Female catkins tassel-like, not persistent; pith compressed; twigs round, resin-dotted ... Betula conspectus1. Female catkins cone-like, persistent; pith triangular; twigs slightly angled .... Alnus conspectus (below)
Alnus Conspectus
| Species | Form | Pith | Buds | Leaves | Cones |
|---|---|---|---|---|---|
| Alnus incana leaf alder Alin |
tall shrub or small tree |
rusty | rounded; stalked |
broadly elliptic; sharp tip; large teeth |
short thin; stout stalk |
| Alnus rubra red alder Alru |
tree | orange to bright red | rounded; stalked |
broadly elliptic; INROLLED; sharp tip; small teeth |
medium; stout stalk |
| Alnus sinuata Sitka alder Alsi |
shrub | whitish | sharp; not stalked |
ovate; sharp tip; large teeth |
long; thin stalk |
| Alnus rhombifolia white alder Alrh |
tree | whitish | rounded; stalked |
elliptic; rounded tip; small teeth |
medium; stout stalk |