Like the morning-glory flower, the tropæolum, or nasturtium, as we usually call it, has several important organs. It has a pistil and stamens, and plenty of rich nectar.
Its corolla, as you know, is large and showy, but it is not in the form of a tube. It is divided, into several distinct pieces called petals. Its calyx, too, is not green, but is colored somewhat like the corolla.
And what is that we see—that long red horn?
That is the tropæolum’s nectary. It is framed from the calyx, in which certain of the sepals have grown together to form this horn of plenty. We are tempted to call it a horn of plenty because it is shaped like a cornucopia and is overflowing with sweet nectar.
It is no wonder the bees and humming birds visit Tropæolum so constantly.
She has provided a most attractive dish of honey for them, but she has so cleverly placed it that they cannot reach it without doing her a service. In our climate bees and humming birds are her constant visitors, but in her own home, in South America, she may have visitors we do not know. She may have a favorite moth whose tongue just fits into her long red horn, or it may be a humming bird that comes to her there, for South America is the home of the humming birds, or it may be a butterfly. We do not know about that, but we do know that her red spur has doubtless grown to its present form to please some beloved bird or insect, and that the bill or tongue of that bird or insect is as long as her red spur.
Why do you suppose Tropæolum makes honey for the insects and the birds?
Why does she love to have them come and take the nectar from her long red horn?