Page:Popular Science Monthly Volume 33.djvu/753

Rh to the ripe stigma or sensitive surface of number two's undeveloped pod. So much alone we can see for ourselves with the unaided eye of outer observation. How much more of the history of this matter will dissection and the microscope finally tell us?

Inside the keel or lower petal of the pea the young pod pushes out its style and brush-like stigma to meet the advances of the fertilizing bee. On the end of the style, at the inner surface, a group of delicate hairs protrudes from the stigma; and it is on these hairs that the bee casually and almost accidentally (so far as he is concerned) deposits the pollen-grains he has carried off from the brother-blossom. Forthwith, each pollen-grain, meeting with the sensitive surface of a sister-style, and recognizing its position, begins to emit a tube of highly vital matter, which bursts out from its side and seeks a vent to penetrate the pod in the exact center of the neighboring flower. Now the hairs, on whose tip the poll engrain has been deposited, are tubular and hollow; and the pollen tubes, running down the style along these pre-established routes, soon reach the little ovules, or undeveloped peas, that lie concealed in the pod within. There it is that the actual, intimate work of fertilization itself really takes place. The vital material of plant number one, laid by in the pollen, enters and mixes with the vital material of plant number two, laid by in the ovule; and from their intermixture and union, in the most physical sense, there springs at last the wonderful little object I see before me—the pea itself, a dormant plantlet, waiting only for heat and moisture to wake it into life, that it may grow into a new and separate individual pea-vine.

Now, note the importance of this act of fertilization. Unless the pollen had reached the ovules in the undeveloped pod, the tiny peas therein contained would never have swollen or developed into perfect seeds at all. The flower in that case would have withered on its stalk, and the pod would have dried up to an abortive and shriveled mass of empty membrane. It was the union of the pollen of one plant with the ovules of another that produced this entirely new individual, a compound and outgrowth, not of one but of two distinct pre-existing organisms. The vital material inside the bee is the vital material of the one, re-enforced and vivified by the diverse vital material of the other.

In order to understand the use and object of this peculiar provision of Nature, whereby every higher plant or animal is the product of two prior individuals whom we call its parents, we must look first more closely at the phenomena of ordinary vegetative growth, and thus see wherein this higher mode of reproduction differs essentially from that simpler and lower function.

All plants (roughly speaking) can produce from certain parts 01 themselves new leaves and branches; and each such leaf, from