RIDDLES IN FLOWERS 2OQ 
our lives. Perhaps we may have chanced to ob- 
serve that the flowers are not all constructed 
alike, but the chances are that we have seen them 
all our lives without discovering this fact. If we 
pluck a few from this dense cluster beside the 
path, we observe that the throat of each is swollen 
larger than the tube beneath, and is almost closed 
by four tiny yellow anthers (Fig. i). The next 
and the next clump may show us similar flow- 
ers ; but after a little search we are sure of find- 
ing a cluster in which a new form appears, as 
shown in Fig. 2, in which the anthers at the open- 
ing are missing, and their place supplied with a 
little forked stigma! The tube below is larger 
than the first flower for about two -thirds its 
length, when it suddenly contracts, and if we cut 
it open we find the four anthers secreted near the 
wide base of the tube. What does it mean, this 
riddle of the bluets ? For hundreds of years it 
puzzled the early botanists, only finally to be 
solved by Darwin. This is simply the little plan 
which the Houstonia has perfected to insure its 
cross -fertilization by an insect, to compel an in- 
sect to carry its pollen from one flower and de- 
posit it upon the stigma of another. Once realiz- 
ing this as the secret, we can readily see how per- 
fectly the intention is fulfilled. 
In order to make it clear I have drawn a pro- 
gressive series of pictures which hardly require 
