12 ELEMENTARY BOTANY. 



4. Those seedlings which instead of two (opposite) cotyle- 

 dons, have but one, as the Lily, Onion, Corn, Wheat, Barley, 

 etc., belong to the group of plants called Monocotyls. The seed- 

 leaf of the Monocotyls seldom resembles a foliage leaf. It is 

 aerial in the Lily family, and in case of some other plants 

 of this group, but it remains mostly underground in or at- 

 tached to the seed, making its real nature difiicult to deter- 

 mine. In seedlings of members of the Pine faraily the 

 number of cotyledons varies in different genera and species, 

 often also in different individuals of the same species. Some- 

 times there are only two, but often four to six, or even as 

 many as ten, forming a whorl at the top of the caulicle. In 

 botanical classification the Pine family is not included in 

 either of the two groups, Dicotyls and Monocotyls, but forms 

 a separate class (Gymnosperms) whose characteristics will be 

 explained later. 



5. In some seeds the leaves are thick and said to be fleshy. 

 These together with the caulicle may occupy the entire cavity 

 within the seed-covering. They are distended by reason of 

 the nourishment with which they are gorged. It is at the 

 expense of this reservoir of food that the embryo or seedling 

 is developed. When the seed-leaves are thin or small the 

 nourishment is stored up around but yet in contact with them. 

 This they absorb for food during the early period of the de- 

 velopment of the seedling. This stage is called Germination. 

 When nearly or quite all the nourishment has been drawn 

 from the seed and seed-leaves, the latter disappear. By this 

 time roots and leaves in sufficient number have been devel- 

 oped to provide food for the plant. 



6. There may be seen between the two cotyledons in case 

 of the bean and many other seeds, a small though conspicu- 

 ous bud. This is called the Plumule. It is present, though 

 usually minute, in every germinating seed ; a lens should be 

 used in its examination. It terminates the upper end of the 

 axis (caulicle) ; the opposite (root) end of this axis has a 

 different structure and it is called the Radicle. The develop- 

 ment of the plumule results in the production of the stem 



