LABOliATOUr STUDIES OF THE FLOWER 



101 



Exercise XXXII. 



The Parts of the Flower in Kelation 

 TO One Another 



Cut a new flower neatly in halves lengthwise. 



Draw the half flower as seen from the cut side, to show: — 



(1) the shape of the pistil; 



(2) the relative positions and lieights of the other parts. 



The sumniit of the flower stem, generally somewhat enlarged, from 

 which the organs spring, is the receplucle. 



Looking down upon or into the flower, endwise, make out the rela- 

 tive position of the sepals, petals, stamens, and cells of the ovary. 



When these have been made out deliuitely, make a diagram of the 

 flower as seen from above, in the following manner: — 

 1st. Represent the ovary in cross section. 



2d. In a circle — if so found in the flower — around the ovary, 

 roughly inilicate the cross sections of the anthers, properly 

 placed as regards direction from the ovary cells. 

 .3d. Represent petals liy arcs of a 

 circle, properly placed ; the 

 arcs may be thickened a 

 little at the middle to repre- 

 sent midribs of the petals. 

 1th. Outside these draw similar 

 figures for the sepals, in 

 the proper places with 

 respect to the other parts. 

 The diagram thus constructed 

 shows the ground plan of the flower. 

 The annexed figure shows the method 

 of constructing such diagrams. 



In case any two parts of the 

 flower are grown together, as two 

 petals, or a petal and a sepal, as 

 sometimes happens, this fact may 

 easily be indicated in the diagram 

 by drawing a dotted line between ^oga. Flower and floral diagram 

 the conjoined members. of Trillium. 



Exercise XXXIII. The Arraxoemext of the Flowers on 

 the Stem or Stejis : or lyfi.ORESCEN'CE 



When flowers come in clusters they ai'e found in one of two differ- 

 ent types of inflorescence. Either a flower, early produced, ends the 

 main stem of the cluster, so that no further growth of the cluster in 

 the line of the axis is possible ; in this case new flowers ;rre produced 

 only on side branches, and these side flowers are younger than that 



