BROADLEAVED TREES OF YOSEMITE NATIONAL PARK 37 



FIELD KEY TO THE BROADLEAVED TREES OF 

 YOSEMITE NATIONAL PARK 



This key considers only the gross characters of trees in question which can be readily noted 

 by the layman. It is of the dichotomous type (regularly branching in pairs). Beginning with No. 1 

 on the left one merely selects the character which fits the tree which is being studied. One is thus 

 referred to the next pair of possibilities by the number noted on the right. Continuing in that 

 manner the observer finally eliminates successive distinguishing characters until the identity 

 of the tree noted is given. 



1. Leaves alternate 2 



1. Leaves opposite 14 



2. Foliage evergreen 3 



2. Foliage deciduous 5 



3. Margins of leaves not toothed; leaves with pungent odor when crushed. Fruit green and 



olivG-like 



California laurel (see page 20) 



3. Margin of leaves often toothed and holly-like in appearance; fruit an acorn 4 



4. Cup of acorn covered with bright yellow "wool." Found from 3,000 to 6,000 ft.; 



common in rocky soils bordering cliffs 



Canyon live oak (see page 16) 



4. Cup of acorn not wooly but scaly; acorn conical. Found up to 2,000 ft.; very rare 



in park 



Interior live oak (see page 18) 



5. Leaves pinnately compound with from 7 to 19 subopposite rounded leaflets; flowers white, 

 in clusters and pealike; fruit a pod with several seeds; twigs with short spines. An 



introduced tree 



Black locust (see page 34) 



5. Leaves simple, not compound 6 



6. Leaves large and deeply cleft into about seven lobes, each with four bristle-tipped 



points; fruit an acorn 



California black oak (see page 14) 



6. Leaves not deeply cleft 7 



7. Margin of leaves not toothed or sinuately lobed (wavy). Fruit an acorn. Found occasionally 



up to 2,000 ft.; very rare in park 



Blue oak (see page 19) 



7. Fruit not an acorn and foliage not as described above 8 



8. Leaves narrow and elongated Willows (see page 6) 



8. Leaves not as noted above 9 



9. Leaves more or less triangular in outline; broadest at base and tapering to a point at 

 apex 10 



9. Leaves not as noted above; either ovate, oblong, or round in outline 11 



10. Leaves large, 2 to 7 inches long, margins finely toothed, thick and leathery in tex- 

 ture, shiny green above and pale green to silvery beneath. Bark heavily ridged 

 and dark gray on large trunks; pale gray on young trees. Common in moist soils up 



to 4,500 feet 



Black Cottonwood (see page 7) 



10. Leaves IV2 to 3 inches long, roundly tapering to a point at the apex; margin of leaf 

 with small teeth; stem or petiole of leaf long and flattened from the side, causing 

 foliage to flutter in slightest breeze. Bark generally smooth and white. Not found 



below 5,000 feet - 



Quaking aspen (see page 9) 



