THE STUDY OF LEAVES 25 



the base, ovate; if widest near the tip, ohovate. If the 

 broad base of an ovate blade is somewhat notched, the 

 blade is cordate or heart-shaped ; if the broad tip has such 

 a notch, it is obcordate. 



Narrower blades when, widest at the middle are elliptic; 

 if widest towards the base, lanceolate; towards the tip, 

 ohlanceolate. 



Any leaves when the sides are rather straight than 

 curved will, if wide, be termed oblong and, if narrow, linear. 



There are blades so broad and rounded as to be called 

 orbicular, others so acutely notched at base as to need 

 the word arrow-shaped. 



Duration of Leaves. — The only difference in the duration 

 of leaves generally considered is that some fall in the 

 autumn while others last through the winter in a green 

 condition ; the words in common use to describe this con- 

 trast are deciduous and evergreen. 



As this is a book intended mainly for summer use when 

 the foliage is in good condition, many will find a difficulty 

 in determining whether the leaves drop off and leave the 

 twigs bare in winter. In general, the thicker and 

 smoother the leaves the more apt they are to remain green 

 through the winter and so be evergreen. This is no 

 absolute difference; it is only a relative one. A mild 

 winter will cause many plants to hold their leaves which 

 in a severe winter they would lose. In the southern 

 states there ate many evergreen plants which in the North 

 are deciduous. 



If the examination of plants should be as early as June 

 and be carefully conducted, nearly every shrub which 

 holds its leaves through the winter can be determined 

 because the old leaves can still be found. At that time 

 the growth of the year can easily be separated from the 

 growth of the preceding year. The contrast in brighter 

 color and a smoothness to the new branches will readily 

 indicate what is new growth. If the last year's twigs still 

 have leaves in the regular places and not leaf-scars, 



