EXPLANATION OF TERMS AS USED IN THE KEY 



ALTERNATE ARRANGEMENT. Only one leaf, leaflet or leaf-scar at 



a node. Literally : 2-ranked. 

 ANGLED MARGIN. Not entirely curved. With some straight places 



and corners. 



APPRESSED. Lying closely to the twig; usually flat. 



ARRANGEMENT. See LEAF ARRANGEMENT. 



AXIL. The angle made with the twig by the upper surface of the leaf, 

 or by the upper margin of the leaf-scar. 



BARK. The woody outside covering of a tree. As the part covered 

 grows in diameter the bark must stretch or split. If it stretches it 

 remains almost smooth and the lenticels are pulled sidewise, so that 

 they form horizontal lines instead of dots. If the baiik splits it be- 

 comes rough or scaly or furrowed. 



BARK SCALES. The pieces into which bark sometimes breaks. They 

 may be large or small; and they may remain on the tree, or flake 

 of? in pieces, or peel either up and down or around the stem. 



BASE. The inner or lower end, as of a leaf or a twig. The opposite 

 of TIP. 



BIPINNATELY COMPOUND. Twice or doubly compound. A pin- 

 nately compound leaf made up of leaflets most or all of which are 

 themselves pinnately compound. 



BLUNT. Rounded. The opposite of POINTED. 



BRANCHES. The twigs of a few years ago. The side divisions of the 

 main stem. 



BRISTLES. Stiff hairs. 



BUDS. See WINTER-BUDS. 



BUD-SCALES. The coverings of buds. Winter-buds may be scale- 

 less or may have from one to many scales. If there are only twq 

 they usually meet without overlapping. If there are several they 

 resemble shingles on a roof. The KEY refers to the largest buds 

 (exclusive of catkins), and considers only those scales which are 

 visible from a single point of view. 



BUNDLE-SCARS. The dots or lines found in a leaf-scar. They in- 

 dicate the location of strands which were concerned with the food 

 supply of the leaf. They are best examined in a leaf-scar of a pre- 

 vious year, and if obscured by dirt will show more clearly if scratch- 

 ed by a knife or a finger-nail. 



CATKIN. A usually long, narrow flower-cluster; ex. willow. Here it 

 is used to denote the bud containing the cluster. A catkin is not 

 included in the descriptions of winter-buds, as it differs so decidedly 

 in size, number of scales, etc. 



CLASPING. Growing around an object. 



CLEFT. Having a wedge-shaped hole. 



29 



