ix 



GROUP 1, WOODY PLANTS 



la. Trees, with erect stem and central trunk, attaining a height of 



6 m. (20 ft.) or more 2. 

 Ib. Shrubs or woody vines, without true tree habit, or attaining 



heights of less than 6 m. (20 ft.) 52. 

 2a. Key for use in earliest spring, for trees which, have flowers 



but no leaves 3. 



2b. Key for use with trees bearing leaves 21. 

 3a. Flowers in catkins, without brightly colored or petal-like parts 



4. 

 3b. Flowers ^not in catkins, either with or without petals 14. 



4a, Leaf-scars and lateral buds 2-ranked, i. e., in two longi- 

 tudinal rows with the third leaf above the first 5. 

 4b. Leaf-scars and buds in three or more longitudinal rows 9. 

 5a. From 1 to 3 bud-scales visible on each leaf-bud 



2b, in FAGACEAE, p. 22. 



5b: From 4 to 7 bud-scales visible on each leaf-bud 6. 

 5c. From 8 to 20 bud-scales visible on each leaf-bud; buds long and 

 . slender; bark of the trunk smooth 8. 



6a. Bundle-scars 5 or more 2b, in URTICACEAE, p. 23. 



6b. Bundle-scars 3 7. 



7a. Twigs bearing numerous dwarf branches thickly covered with 

 crowded leaf-scars (Birch) BETULACEAE, p. 21. 



7b. Twigs without dwarf branches (Ironwood) 



9a, in BETULACEAE, p. 22. 



8a. Trunk cylindrical or nearly so 2a, in FAGACEAE, p. 22. 

 8b. Trunk prominently fluted with longitudinal ridges 



Ib, in BETULACEAE, p. 21. 



9a. Bundle-scars 3 in each leaf-scar 10. 



9b. Bundle scars more than 3 in each leaf-scar 12. 



lOa. Pith divided into separate cavities by transverse partitions 



la, in JUGLAINDACEAE, p. 21. 

 lOb. Pith not partitioned 11. 

 lla. Buds small, with only one external bud-scale 



Ib, in SALICACEAE, p. 19. 

 lib. Buds with more than one outer bud-scale 



la, in SALICACEAE, p. 19. 



12a. Buds clustered near the tips of the twigs 



Ib, in FAGACEAE, p. 22. 

 12b. Buds not clustered at the tips of the twigs 13. 



