ANALYTICAL KEY 



a. TREES. iFor next related division go to page 9*.) 

 b. Leaves small or narrow, usually needle- or awl-shaped (Ptne family'). 

 0. Leaves always present, i. n., tree evergreen. 



d. Leaves in clusters of two or more on ordinary branches (Pine). 

 e. Leaves five in a cluster. White Pine, PINTTS STROBTJS (p. 30). 



e. Leaves two or three in a cluster, 

 ft Cone scales without spines or prickles. 

 g. Leaves long, t. e., 9-16 cm. Red Pine, PINTTS RESINOSA (p. 31). 



g. Leaves short, t. e., 2-4 cm. Jack Pine, PINTJS BANKSIAWA (p. 31). 

 f. Cone scales armed with a spine or prickle. 

 g. Leaves rigid. 

 h. Leaves two in a cluster. Jack Pine, PINTTS BANKSIANA (p. 31). 

 h. Leaves three in a cluster. Pitch Pine, PINTTS RIGIDA (p. 31). 



g. Leaves flaccid. 

 h. Scale spine minute, i. e., i mm. or less in length. 



Yellow Pine, PINtTS ECHINATA (p. 31). 

 h. Scale spine 2—3 mm, in length. 



Jersey Pine, PINTJS VIRGINIANA (p. 31). 

 d. Leaves single. 

 e. Leaves not opposite, needle-shaped. 



Hemlock, TSTTGA CANADENSIS (p. 31), 

 e. Leaves opposite. 

 f. Fruit a cone of separate scales; leaves scale-shaped. 



Arbor Vitae, THUJA OCCIDENTALIS (p, 32). 

 f. Fruit a berry; leaves needle- or scale-shaped. 



Red Cedar, JUNIPERTJS VIRGINIANA (p. 32), 

 c. Leaves absent part of the year, i. e., tree deciduous; leaves many in a 

 cluster on a short branch. . Tamarack, LARIX XARICINA (p. 31). 



b. Leaves not needle- or awl-shaped; trees not evergreen. 

 u. Leaves and branches opposite (p. 6). 

 d. Inflorescence white. 

 e. Corollas greenish, surrounded by a showy white involucre. 



Flowering Dogwood, CORNTTS FLORIDA (p. 100). 

 e. Corollas white; involucre wanting. 



Black Haw, VIBURNUM LENTAGO (p. 119). 

 d. Inflorescence not white. 

 e. Flowers appearing decidedly before the leaves (p. 6). 

 f. Bark whitish to grayish, smooth except on basal parts of large trees; 

 leaves simple (Maple). 

 g. Petals none; fruit woolly; leaves deeply lobed. 



Silver Maple, ACER SACCHARINUM (p. 91). 

 g. Petals present; fruit smooth; leaves somewhat lobed. 



Red Maple, ACER RUBRUM (p. 91). 

 f , Bark rough except on the smaller branches ; twigs coarse ; leaves 

 compound (Ash). 

 g. Old bark deeply furrowed; calyx present. 



White Ash, FRAXINUS AMERICANA (p. 106). 

 * The words, "for next related division go to" are to be understood with sim- 

 ilar references v/hich follow. 



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