PROBLEM 15 41 



4. Make a drawing (diagram) to show how a bee helps to 

 pollinate butter and eggs. 



Problem 15 : Special directions for the study of some fall 

 flowers. (Extra.) * 



The Evening Primrose (Onagra biennis). — The habitat pre- 

 ferred by this flower is dry fields, roadsides, or waste places. The 

 yellow flowers are found in long, upright, densely crowded clusters. 

 A flower cluster in which the individual flowers have no flower 

 stalks or pedicles, with one main axis to the cluster, is called a spike. 

 Notice that young and old flowers and fruits are all on the same 

 cluster. Where are the youngest flowers located in the cluster? 

 Is there any flower at the end of the main stalk ? Could you deter- 

 mine in advance the length of the flower cluster? Such a cluster 

 is said to be indeterminate. Why? Study a single open flower. 

 Note the calyx and corolla. Are the parts distinct ? How many 

 petals do you find ? Notice that there are eight stamens and that 

 the stigma is four-parted. Cut the ovary in cross section, and 

 see how many locules (spaces) there are. 



When a flower has each circle of parts, as the sepals, petals, 

 stamens, and pistils, made up of a certain number of divisions, or 

 when they appear in multiples of that number, the flower is said 

 to be symmetrical. Here we see a very striking example of sym- 

 metry in a flower. 



The chief attraction to insects is the nectar, which is formed in 

 nectar glands at the base inside the slender tubular corolla. In- 

 formation is given to the insects of the contents by a faint, sweet 

 odor. This flower is not visited by many day-flying insects. 

 Can you determine the names of any that do come by day? At 

 night the flower opens more widely and the scent becomes much 



1 To the Teacher. — If the work on flowers is taken up in the spring, field work 

 should result in the collection of jack-in- the-pulpit, oak, willow, skunk cabbage, 

 grasses, and also many wild flowers which show special adaptations for cross-polli- 

 nation. In the fall butterfly weed, Salvia, turtlehead, and various composites 

 show wonderful adaptation. Original investigation on simple problems of this 

 kind have been found by the writer to be the best means of stimulating certain 

 better prepared students to take an abiding interest in this work. Two or three 

 sample investigations are given here that might be used by the student as a form in 

 making reports on other flowers. 



