. Elementary botany. Botany. SEED DISTRIBUTWA'. 371 thus exposed. The dark brown achenes stand over the surface of the recep- tacle, each one tipped with the long slender beak of the ovary. The "pap- pus," which is so abundant in many of the plants belonging to the composite family, forms here a pencil-like tuft at the tip of this long beak. As the involucral bracts dry and curve down- ward, the pappus also dries, and in doing so bends downward and stands outwanl, brist- ling like the spokes of a fairy wheel. It is an interesting coincidence that this takes place simultaneously with
. Elementary botany. Botany. SEED DISTRIBUTWA'. 371 thus exposed. The dark brown achenes stand over the surface of the recep- tacle, each one tipped with the long slender beak of the ovary. The "pap- pus," which is so abundant in many of the plants belonging to the composite family, forms here a pencil-like tuft at the tip of this long beak. As the involucral bracts dry and curve down- ward, the pappus also dries, and in doing so bends downward and stands outwanl, brist- ling like the spokes of a fairy wheel. It is an interesting coincidence that this takes place simultaneously with the pappus of, all the seeds of a head, so that the ends of the pappus bristles of ad- joining seeds meet, forming a many-sided dome of a delicate and beautiful texture. This causes the beaks of the achenes to be crowded apart, and with the leverage thusbrought to bear upon the achenes they are pried off the receptacle. They are thus in a position to be wafted away by the gentlest zephyr, and they go sailing away on the wind like a miniature parachute. As they come slowly to the ground the seed is thus carefully low- ered first, so that it touches the ground in a position for the end which contains the root of the embryo to come in contact with the Fig. 473. Lactuca Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Atkinson, George Francis, 1854-1918. New York, H. Holt
Size: 1127px × 2217px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublisher, booksubjectbotany
