13^ LEAVES. 



All leaves that are not green are said to be Coloured, 

 as in the Three-coloured Amaranthus, and Beet. 



Variegated. — Dr. Smith applies this term to the 

 white and yellow spots which are the effect of disease. 

 The Ladies Striped-grass, so well known in almost ev- 

 ery garden, loses it variegated appearance when trans- 

 ferred to the fields, though its luxuriant growth in the 

 former situations, seems to indicate that it is not exclu- 

 sively the effect of disease. The same observations 

 are applicable to the Aucuba or Golden Plant of Japan, 

 and therefore it is probable, that an unnatural exposure, 

 perhaps to the action of light, may have produced this 

 effect. 



An Aculeate leaf is covered with spines as in Rkexia. 

 When the serratures of a leaf terminate in sharp prick- 

 les it is said to be aculeate-serate. 



A leaf destitute of every kind of pubescence is said to 

 be Naked. 



8. SUBSTANCE. 



With regard to Substance, Membranaceous leaves 

 are thin, flexible and almost transparent, as in Penny 

 wort. Coriaceous are thick and firm like leather, as in 

 Laurel and Oleander, and Succulent or fleshy leaves are 

 filled with pulp, as in the Ice plant and Aloe. 



The Onion is an example of a Tubular leaf, and that 

 of the Water Lobelia, has two contiguous cavities or 

 cells. Fig. 51. 



A thick oblong blunt leaf with a cartilaginous margin 

 is said to be Lingulate or Tongue- shaped. It occurs 

 but rarely. 



An Ensiform or sword-shaped leaf, is two-edged, 

 erect, tapering to a point, with two convex or gibbous 



