fiO 



OF LEAVES. 



Leaves considered icith regard to the manner in which they succeed each other in uij"- 

 /erent stages of the plant. 



1. Seminal, leaves which come up with the plant when it first ap- 

 pears above the surface of the earth ; as in the garden bean ; these 

 leaves are only the cotyledons, or lobes of the seed, which, after nour • 

 ishi)ig the young plant, decay. 



2. Primordial, leaves growing immediatelj^ after the seminal 

 leaves, and resembling them in position, form, and size. The pri- 

 mordial leaf, according to the fanciful idea of a French botanist, is a 

 sketch which nature niakcs before the perfection of her work. 



3. Characteristic, leaves which are found in the mature state of the 

 plant ; or according to the idea above advanced, nature, in them, 

 perfects her design. 



It is not always, however, that this process, with regard to change 

 of leaves, takes place ; as in many cases, the proper, or characteris- 

 tic leaf, is the only one which appears. 



Form of Leaves. 



The funn of the leaf is expressed by various terms borrowed from 

 the names of diiferent objects; as palmate, hand-shaped; digitate. 

 from digitus, the finger, &c. We will illustrate some of the most 

 common forms of simple leaves, leaving you to consult the vocabu- 

 lary for many terms, which it would be too tedious to attempt to de- 

 fine in the body of this work. 



Fig. 38. 



Orbicidar, or the round leaf; the Naslurtion affords an example of 

 this kind, (See Fig. 38, a;) this is also peltate, having its petiole in- 

 serted into the centre of the leaf, and thus resembhng a shield. 



Renifonn, (from the Latin ren, the kidney,) or as^it is sometimes 

 called kidney-form J the Ground-ivy {Glechomci) has a leaf of this 

 kind, (See Fig. 38, h ;) it is crenate, or has a margin with scalloped 

 divisions ; ciliate, being fringed with hairs, like eyelashes. 



Cordate, (from the Latin cor, the heart,) or heart-shaped. Fig. 3F, 

 c, represents a cordate leaf with an acuminated point, that is, acute 

 and turned to one side ; the margin is serrated, or notched like the 

 leeth of a saw; this kind of leaf may be seen inthc Aster cordifolinm, 

 or aster with a heart-shaped leaf. 

 Fig. 39. 



■ I 



Ovate, obovate, 

 oval J these are 

 terms derived from 

 the Latin ovum, an 

 egg ; suppose the 

 figure at 39, a, to 

 represent an egg; you observe that one end is broader than the 

 other ; now, if to this broad end you add a petiole, prolonging it into 



Leaves with respect to succession- 

 ale— Ovate -Ohovate— OvaL 



-Form of Leaves— Orbictilar— Renifonn— Cord- 



