Decompound Leaves. 59 



palmate or pinnate type ? Most decompound leaves of the 

 former type divide continually into three parts forming a 

 ternately decompound leaf. Columbine and thalictrum 

 (meadow-rue) have such leaves. Some acacias have pin- 

 nately decompound leaves. Have all the leaflets petioles in 

 such leaves ? 



Study the leaves which you have not been able to 

 describe; that is, try again. Have you a palmately decom- 

 pound leaf with pinnate leaflets? A leaf pinnate below 

 and pinnately lobed above ? A leaf with a few leaflets at 

 the base of an entire blade ? A leaf with three or more 

 ribs running from base to apex ? Try to make out the 

 plan of the skeleton first. Then tell how the leaf is built 

 upon the skeleton. Compare forms to those of common 

 objects. Make descriptions as brief as possible, using the 

 adjectives with which you have long been familar, as well 

 as those which you have learned in these exercises. Usu- 

 ally the most important characters should be first given, 

 but you must pay some attention to sound, as well as sense. 

 Write out a description of an elderberry leaf (or any pin- 

 nate leaf), and then read the following: Elderberry leaves 

 are pinnately y-foliolate, extipulate and borne on petioles 

 shorter than the spaces between the pairs of thin, smooth 

 leaflets, which are nearly elliptical, and serrate from near 

 the acute base to the abruptly acuminate apex. The lateral 

 leaflets are sessile, or nearly so, and slightly one-sided, the 

 upper edge being shorter than the lower. The general out- 

 line of the entire leaf is ovate, the length on old trees eight 



