50 
OF LEAVES. 
heaves considered with regard to the manner in which they succeed each other in 
yerent 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- 
ishing the young plant, decay. 
2. Primordial, leaves growing immediately 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 makes 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 form of the leaf is expressed by various terms borrowed from 
the names of different objects ; as palmate, hand-shaped ; digitate, 
^rom 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. 
Orbicular, or the round leaf; the Nasturtion 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 resembling a shield. 
Reniform, (from the Latin ren, the kidney,) or as it is sometimes 
called kidney-form ; the Ground-ivy (Glechoma) has a leaf of this 
kind, (See Fig. 38, b ;) it is crenate,- or has a margin with scallopecj 
divisions ; ciliate, being fringed with hairs, like eyelashes. 
Cordate, (from the Latin cor, the heart,) or heart-shaped. Fig. 38, 
c, represents a cordate leaf with an acuminated point, that is, acute 
and turned to one side ; the margin is serrated, or notched hke the 
teeth of a saw; this kind of leaf may be seen in the Aster cordifoliim, 
or aster with a heart-shaped leaf 
Fig. 39. 
Ovate, obovate, 
oval ; 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— Form of Leaves— Orbicular— Renifonn—Cord- 
atfi — Ovate- -Obovate— Oval. 
