66 STRUCTURE AXJ) rilYSIOLOGY OF SEED PLANTS 



Make a tabular list of the parts of the flower, beginning 

 with the sepals, giving the order of parts and the number in 

 each set. 



45. The flower of the tulip. ^ 



A. Make a sketch of a side view of the well-opened flower as it appears 

 when standing in sunlight. Observe that there is a set of outer flower 

 leaves and a set of inner ones.'^ Label the outer set sepals and the inner 

 set petals. In most flowers the parts of the outer set are greenish, and 

 those of the inner set of some other color. It is often convenient to 

 use the name perianth (meaning around the flower) for the two sets 

 taken together. Note the white waxy bloom on the exterior surface 

 of the outer segments of the perianth. What is the use of this ? Observe 

 the manner in which the inner segments of the perianth arise from the 

 top of the flower stalk and their relation to the points of attachment of 

 the outer segments. In a flower not too widely opened note the relative 

 position of the inner segments of the perianth, how many wholly outside 

 the other two, how many wholly inside, how many with one edge in 

 and one edge out. 



B. Remove one of the sepals by cutting it off close to its attachment to 

 the peduncle, and examine the veining by holding it up in a strong 

 light and looking through it. Make a sketch to show the general out- 

 line and the shape of the tip. 



C. Examine a petal in the same way, and sketch it. 



D. Cut off the remaining portions of the perianth, leaving about a quarter 

 of an inch at the base of each segment. Sketch the upright, triangular, 

 pillar-like structu.re in the center, — label it pistil; sketch the organs 

 which spring from around its base, and label these stamens. 



Note the fact that each stamen arises from a point just above and 

 within the base of a segment of the perianth. Each stamen consists of 

 a somewhat conical or awl-shaped portion below, the filament, sur- 

 mounted by an ovate-linear portion, the anther. 



E. Sketch one of the stamens about twice natural size and label it x 2. 

 Is the attachment of the anther to the filament such as to admit of 

 any nodding or twisting movement of the former ? In a young flower 

 note the tubular pouches, or pollen chambers, of which the anther is 

 composed, and the slits by which these open. Observe the dark-colored 

 pollen which escapes from the anther cells and adheres to paper or to 

 the fingers. Examine a newly opened anther with the lens and sketch 

 it. Cut thin cross sections of an unopened anther and examine with l.p. 

 Note that there are four pollen chambers, two on each side. 



1 Tulipa Uttsiiarlaiia. ^ Best seen iu a flower which is just opening. 



