202 PRACTICAL COURSE IN BOTANY 



serted under the pistil. ' ' These terms should be remembered, 

 as the distinction is an important one in plant evolution. 



219. Summary of observations. — In the flower just ex- 

 amined, we found that there were four sets of floral organs 

 present — sepals, petals, stamens, and pistil ; that the indi- 

 vidual organs in each set were alike in size and shape ; that 

 there were the same number, or multiples of the same 

 number of parts in each set, and that all the parts of each set 

 were entirely separate and disconnected, the one from the 

 other, and from those of the other cycles. Such a flower is 

 said to be : — 



Perfect, that is, provided with both kinds of organs essen- 

 tial to the production of seed — stamens and pistil. 



Com-plete, having all the kinds of organs that a flower can 

 have: viz. two sets of essential organs, and two sets of 

 floral envelopes. 



Symmetrical, having the same number of organs, or mul- 

 tiples of the same number, in each set. 



Regular, having all the parts of each set of the same size 

 and shape, as in the wild rose and bellflower, or if different, 

 arranged in regular order or pairs, so that there will be a 

 correspondence between the two sides of the flower, as in the 

 violet, sweet pea, sage, and larkspur. For convenience, the 

 two kinds may be distinguished as complete and bilateral 

 regularity, respectively. 



The opposites of these terms are : imperfect, incomplete, 

 asymmetrical or unsymmetrical, and irregular. 



Note that regularity refers to form, symmetry to number 

 of parts, and that a flower may be perfect without being 

 complete. 



220. Dissection of a typical dicotyl flower. — (Poppy, 

 flax, pink, tomato, linden, etc., can be substituted for the 

 specimen used in the text.) Gently remove the sepals and 

 petals from a wallflower, stock, mustard, or other cress 

 flower, lay them on the table before you in exactly the order 

 in which they grew on the stem, and sketch them. How 



