A later stage shows the hypocotyl lifting the cotyledon upward.
The part of the stem below the cotyledons (hypocotyl) commonly plays the greater part in bringing this about.
Below the sheathing leaf is a narrow length which will be distinguished as the hypocotyl, and where growth is very active.
If the cotyledon be shaded and the light be permitted to fall on one side of the hypocotyl, no heliotropic curving takes place.
The rodlike part is called the hypocotyl (meaning under the cotyledons).
A lens focusses the light from O, on the hypocotyl, and that from O', on the tip of the cotyledon.
Contrary to generally accepted view the hypocotyl not only perceives but responds to light.
The belief that the hypocotyl of Setaria is incapable of perceiving stimulus is thus without any foundation.
Hence considerable doubt may be entertained as regards the supposed absence of perception in the hypocotyl of Setaria.
In consequence the hypocotyl forms an arch, dragging after it the bulky cotyledons.
The part of a plant embryo or seedling that lies between the radicle and the cotyledons. Upon germination, the hypocotyl pushes the cotyledons above the ground to develop. It eventually becomes part of the plant stem. Most seed-bearing plants have hypocotyls, but the grasses have different, specialized structures.