Studies of Selected Spermatophytes. 229 



and stigmas are so placed that, as the insect goes out 

 through one of these, pollen is rubbed off on the upper 

 part of its body, and afterward, on leaving another flower, 

 this pollen is left on the stigmas and a new supply is 

 removed. The device to secure cross pollination here 

 worked out is admirable for its simplicity and efficiency. 

 We wonder why this plant, and orchids in general, do not 

 occur more commonly, since cross pollination has been so 

 well provided for by them, and a vigorous brood is in con- 

 sequence to be expected. It will be worth while in fol- 

 lowing up this question to observe whether the necessary 

 insect visits actually take place. The flowers of Cypripe- 

 dium insigne are said to last forty days and those of 

 Cypripedium villosum seventy days. Does this long life 

 of the flower seem to indicate uncertainty on the part of 

 insect visits ? After fertilization has been accomplished 

 we find that the seeds resulting are numerous and very 

 minute. The large number of course increases the chance 

 of offspring, but the diminutive size of the seeds must 

 result in great loss before and during germination. The 

 student can think out for himself in what ways loss would 

 be likely to occur. 



Salix. (Obtainable species.) 



What sort of habitat do the willows prefer ? Note the 

 form of the willow, its habit of branching, and the char- 

 acter of its branches. Cut off a small willow branch and 

 place it in a jar of water in a warm room, and note how 

 adventitious roots are formed after a time. The branches 

 of some willows are quite brittle, and falling off frequently 

 become rooted in the mud, and in this way multiplication 

 may take place. How early in the spring do the leaves 

 and flowers appear? Which appear first? The flowers 



