222 FLOWER-LAND. 



(iii. ) Carbon is a solid and elementary substance, that is, chemists 

 have not found it to be a composition of other substances. You 

 can easily see it, for the black lead of a common pencil is 

 carbon. Pure crystallized carbon is very valuable, as the beau- 

 tiful diamond. Under certain conditions carbon unites with 

 oxygen gas, and so forms carbon dioxide, or carbonic acid gas. 



Carjbon. See Atmosphere iii. 



Carbonic Acid Gas. See Atmosphere ii. 



Cell. Sometimes, as in the formation of pollen, the nucleus of the 

 mother cell divides into four parts, around each of which the proto- 

 plasm gathers, and a cell wall forms, so that each becomes a new 

 and perfect cell. 



When the nucleus of a mother cell divides into many parts, 

 or new nuclei, each becoming surrounded by protoplasm before 

 new walls are formed, it is called free cell formation. This takes 

 place in the formation of the endosperm in the embryo bags of 

 ovules. 



See chlorophyll corpuscle dividing, in Fig. 163, b, b 1 , b" ; and 

 endosperm cells which are being formed by free cell formation in 

 Fig. 113 S, p. 134. 



Collar. The part at which the stem ends and the root begins! 



Cortex. Used collectively of that which is outside the cambium ; 



and so including (i.) the phloem or bast (secondary cortex), and 



(ii.) the fundamental tissue, etc., which is outside the bast (primary 



cortex). Sometimes used to mean the part outside the bast only 



(primary cortex). 



Dehisce nee. When a capsule splits or opens by the separation of 

 its carpels, i.e. y down the dissepiments, the dehiscence is septicidal,* 

 or splitting down the septa or dissepiments. When, however, -the 

 carpels split open down the dorsal suture, the dehiscence is called 



* From the Latin "septum" the partition or dissepiment,, and 

 " ccedo" I cut. ... 



