146 ESSENTIALS OF BOTANY 



the top, and three lobes of the stigma. Make a sketch of these parts 

 about twice natural size, and label them x 2. Touch a small camel's- 

 hair pencil to one of the anthers, and then transfer the pollen thus 

 removed to the stigma. This operation is merely an imitation of 

 the work done by insects which visit the flowers out of doors. Does 

 the pollen cling readily to the rough stigmatic surface ? Examine this 

 adhering pollen with the two-inch objective, and sketch a few grains 

 of it, together with the bit of the stigma to which it clings. Com- 

 pare this drawing with Fig. 12]. Make a cross-section of the ovary 

 about midway of its length, and sketch the section as seen through 

 the magnifying glass. Label the three chambers shown cells of the 

 ovary ^ or locales, and the white egg-shaped objects within ovules.^ 



Make a longitudinal section of another ovary, taking pains to 

 secure a good view of the ovules, and sketch as seen through the 

 magnifying glass. 



Making use of the information already gained and the cross- 

 section of the ovary as sketched, construct a diagram of a cross- 

 section of the entire flower on the same general plan as those shown 

 in Fig. 116.3 



Split a flower lengthwise * and construct a longitudinal section of 

 the entire flower on the plan of those shown in Fig. 114, but showing 

 the contents of the ovary. 



174. The Flower of the Buttercup. — Make a diagram of the 

 mature flower as seen in a side view, looking a little down into it. 

 Label the pale greenish-yellow, hairy, outermost parts sepals, and 

 the larger bright yellow parts above and within these petals, and 

 the yellow-knobbed parts which occupy a good deal of the interior 

 of the flower stamens. 



Note the difference in the position of the sepals of a newly opened 

 flower and that of the sepals of a flower which has opened as widely 

 as possible. Note the way in which the petals are arranged in relation 



■' Notice that the word cell here means a comparatively large cavity, and is 

 not used in the same sense in which we speak of a wood-cell or a pitli-cell. 



2 The section wiU be more satisfactory if made from an older flower, grown 

 out of doors, from which the perianth has fallen. In this case label the con- 

 tained objects seeds. 



8 Consult also the footnote to Sect. 172. 



* One will do for an entire division of the class. 



