162 STUDY OF COMMON PLANTS. 



c. Where the numerous silky hairs are attached. 

 2. Study the flower itself. 



a. How many stamens are there ? 



b. Is a nectary (organ that secretes nectar) present? 



II. Examine next the pistillate catkins. 



1. In what respects do they differ from the staminate 



ones ? Are the scales alike in both ? 



2. Note the peculiarities of the pistil. 



a. Its form. 



b. Stalked or sessile ? 



c. Number and form of stigmas. 



d. How many carpels compose the ovary ? 



e. Is there a nectary ? 



III. Are the flowers visited by insects? Enumerate the 

 attractions adapted to secure insect visits. 1 



Fruits. 



When the fruits are ripe, observe their structure and 

 mode of dehiscence, the attachment of the seeds and their 

 peculiarities, particularly their means of dissemination. 



Comparison with Other Species. 



Some days later, as soon as they are in proper condition 

 for examination, study the catkins of other kinds of willows 

 (Salix cordata, Muhl., S. lucida, Muhl., or other available 

 species), and note all the characters in which they agree 

 with the species already studied. 



POPLARS. 



In the same manner make a careful study of one or 

 more common species of poplar and compare them with 

 the willows. 



1 Cf Muller, Fertilization of Flowers, p. 524. 



