IS BOTANY FOR BEGINNERS. j Ch. 



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 HEPATICA triloba is that 

 species of the Hepatica which has leaves with three divisions, 

 called lobes ; the VIOLA 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 (radio?,) 

 cauline, 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 1 



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 

 take place ? 



188. What are some of the terms which express the mode of inser- 

 tion of the leaf? 



189. What terms express the position oHhe leaf* 



