"The stem immediately above the cotyledons will be called the epicotyl or plumule" (OED).

"With seedlings, the stem‥has been called by many botanists the hypocotyledonous stem, but for brevity sake we will speak of it merely as the hypocotyl" (OED).

"I venture to advance the hypothesis of Pangenesis, which implies that the whole organization, in the sense of every separate atom or unit, reproduces itself. Hence ovules and pollen-grains—the fertilized seed or egg, as well as buds—include or consist of a multitude of germs thrown off from each separate atom of the organism" (OED).