ASEXUAL REPRODUCTION 7 I 



169. Itisnotinall cases necessary that a seed should be formed 

 in order that a new plant may be developed. Many peren- 

 nials also multiply by a process called budding, which consists 

 essentially of the development from some part of the parent 

 stock of a shoot which ultimately becomes an independent 

 plant. The shoot may spring from the roots, from underground 

 stems, from runners or branches where they touch the sub- 

 stratum or even from leaves. Some species belonging to the 

 group of seed-bearing plants have adopted this method of repro- 

 duction almost to the exclusion of the formation of seeds. 



Classes of Plants 



170. All the so-called flowering plants have one character- 

 istic in common, which is the formation of a reproductive body, 

 the seed, developed from the ovule after fertilization, and con- 

 sisting essentially of an embryo enclosed in a protective seed 

 coat. This group of plants is called Spermatophytes and con- 

 sists of two divisions, the Angiosperms and the Gymnosperms. 



171. The Angiosperms are those seed-bearing plants in which 

 the ovules are enclosed in the cavity of an ovary. Of these 

 there are two classes, the Monocotyledons and the Dicotyle- 

 dons. The difference between these two classes is shown 

 in the following table: 



Angiosperms 



DICOTYLEDONS MONOCOTYLEDONS 



1. Two seed leaves. i. One seed leaf. 



2. Leaves netted veined and 2. Leaves parallel veined with 

 with broken margin. margin entire. 



3. Parts of flowers in 4s or 5s. 3. Parts of flowers in 3s. 



4. Vascular bundles of the 4. Vascular bundles of the stem 

 stem in a single circle form- scattered and no distinction of 

 ing two concentric cyHn- wood and bark. 



ders of wood and bark. 

 Either of the characters, 2, 3, or 4, may in some cases fail to apply. 



