18 BOTANY FOR BEGINNERS. [Ch. IX 
181. Some plants are destitute of leaves; they are then call- 
ed Aphyllous, which term signifies wanting leaves. 
182. In determining the species of plants, the leaves are 
much regarded. Specific names are often given from some cir- | 
cumstance of the leaf; for example, the Heparica triloba is that 
species of the Hepatica which has leaves with three divisions, 
ealled lobes ; the Viota rotundifolia is a species of violet with 
round leaves. 
183. A knowledge of the various appearances presented by 
leaves, is of great importance ; in order to become acquainted 
with all their varieties, considerable practice in the analysis of 
plants is necessary. Engravings will assist you in understand- 
ing definitions, but you must consult nature. There are many — 
terms to express the varieties observable in leaves; we shall 
here explain some of the most important. 
184. 1. Seminal leaves are those which come up with the 
plant when it first appears above the surface of the earth; as in 
the garden bean: these leaves are the cotyledons, or lobes of 
the seed, which, after nourishing the young plant, decay. 
185. 2. Primordial leaves succeed the seminal ones, and 
resemble them in position, form, and size. The primordial 
leaf, according to the fanciful idea of a French botanist, is a 
sketch which nature makes before the perfection of her work. 
186. 3. Characteristic leaves are found in the mature state 
of the plant; or according to the idea above advanced, nature 
here perfects her design. 
187. It is not always, however, that this process with regard 
to change of leaves takes place; as in many cases the proper, 
or characteristic leaf, is the only one which appears. 
188. There are many terms to express the mode of insertion 
of the leaf; such as radical, growing from the root (radiz,) 
rauline, growing from the stem (caulis,) &c. 
189. To express the position of leaves, we find the terms. 
opposite, alternate, &c. 
181. What are plants destitute of leaves called ? 
182. Is the leaf noticed in determining the species of plants? 
183. What is the best way of learning the varieties of leaves? 
184, Describe the seminal leaf. 
185. Describe the primordial leaf. 
186. Describe the characteristic leaf. 
187. Does this process with respect to the change of leaves always 
cake place ? ; 
188. What are some of the terms which express the mode of inser- 
tion of the leaf? 
189. What terms express the position of the leaf? | 
