122 LEAVES. 



them by terms which denote their respective inser- 

 tions. The flower is sometimes accompanied by leaves 

 of a different size or shape from the others, and these 

 are termed Floral leaves. The stalk of Parnassia, 

 having only a solitary leaf is said to be Unifoliate, and 

 the Lily of the Valley having two is Bifoliate, but it is 

 rare to see leaves so few, or their number so invari- 

 able. 



When the petioles are inserted into opposite points 

 of a stem, as in the Lilac, they are said to be Opposite, 

 and when they arise successively from the different 

 sides of a stem, as in the Cherry and Pear trees, they 

 are said to be Alternate. 



Stellate or Verticillate leaves, Fig, 45, grow in a cir- 

 cle around the stem, as in the common Red Lily, Indian 

 Cucumber, and Galium. 



When several leaves are inserted together as in the 

 Hackmatack, they are said to be Fascicled or Tufted ; 

 and Imbricated when they overlap and enclose each 

 other, like tiles on a house top, as in White Cedar and 

 Juniper. 



When opposite leaves alternately cross each other 

 at right angles as in Bone-set, they are Decussated. 



Distickal or Two-ranked leaves spread in two direc- 

 tions, as in the Hemlock tree, but if leaves thus dispos- 

 ed arise from two opposite points of a stem, they are 

 said to be Bifarious. 



Those leaves are Floating, which we see on the 

 surface of the water, as in Pond Lilies ; those are Im- 

 mersed which are beneath it, as Water Violet and Valis- 

 neria ; and those are Emersed, which are seen rising 

 above its surface. 



Some leaves are Oppressed towards the stem, some 

 Depressed close to the ground, as in the Carpet weed ; 



