FREE BOOKS

Author's List




PREV.   NEXT  
|<   12   13   14   15   16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   31   32   33   34   35   36  
37   38   39   40   41   42   43   44   45   46   47   48   49   50   51   52   53   54   55   56   57   58   59   60   61   >>   >|  
or this purpose abundant material is indispensable. It is better not to attempt these lessons on seeds at all, unless there is material enough for personal observation by all the pupils. After this preliminary work has been done, the names of the parts can be given to the pupils. They may be written under each drawing thus,--A=Caulicle;[1] B=Cotyledons; C=Roots; D=Plumule. The whole plantlet in the seed is the _embryo_ or _germ_, whence the sprouting of seeds is called _germination_. [Footnote 1: The term radicle is still in general use. The derivation (little root) makes it undesirable. Dr. Gray has adopted caulicle (little stem) in the latest edition of his text-book, which I have followed. Other writers use the term hypocotyl, meaning under the cotyledons.] I consider this the best order to study the seeds because in the Morning-Glory the cotyledons are plainly leaves in the seed; and in the Squash or Sunflower[2] the whole process is plainly to be seen whereby a thick body, most unlike a leaf, becomes an ordinary green leaf with veins.[3] In the Sunflower the true leaves are nearly the same shape as the cotyledons, so that this is an especially good illustration for the purpose. Thus, without any hint from me, my pupils often write of the Bean, "it has two thick leaves and two thin leaves." In this way the Bean and Pea present no difficulty. The cotyledons in the first make apparently an unsuccessful effort to become leaves, which the second give up altogether. [Footnote 2: The large Russian Sunflower is the best for the purpose.] [Footnote 3: These lessons are intended, as has been said, for children over twelve years of age. If they are adapted for younger ones, it is especially important to begin with a seed where the leaf-like character of the cotyledons is evident, or becomes so. Maple is excellent for the purpose. Morning-Glory is too small. Squash will answer very well. I think it characteristic of the minds of little children to associate a term with the first specimen to which it is applied. If the term cotyledon be given them first for those of the Bean and Pea they will say when they come to the Morning-Glory, "but those are _leaves_, not cotyledons. Cotyledons are large and round." It will be very difficult to make them understand that cotyledons are the first seed-leaves, and they will feel as if it were a forced connection, and one that they cannot see for themselves.] The teacher's object
PREV.   NEXT  
|<   12   13   14   15   16   17   18   19   20   21   22   23   24   25   26   27   28   29   30   31   32   33   34   35   36  
37   38   39   40   41   42   43   44   45   46   47   48   49   50   51   52   53   54   55   56   57   58   59   60   61   >>   >|  



Top keywords:

leaves

 
cotyledons
 

purpose

 
Footnote
 

Morning

 

Sunflower

 

pupils

 

Squash

 

material

 

children


plainly

 

lessons

 
Cotyledons
 

intended

 

altogether

 

Russian

 
present
 

difficulty

 
indispensable
 

effort


unsuccessful
 

apparently

 

difficult

 

understand

 

applied

 

cotyledon

 

teacher

 

object

 

forced

 

connection


specimen

 

associate

 

character

 
important
 
adapted
 

younger

 

evident

 
characteristic
 

answer

 

abundant


excellent

 

twelve

 

radicle

 

general

 

derivation

 
preliminary
 

sprouting

 
called
 

germination

 

caulicle