. Elementary botany. Botany. SEED DISPERSAL. 461 1' .( thus exposed. The dark brown achenes stand over tlie surface of the recep- tacle, each one tipped with the long slender beak of the ovary. The â ⢠pap- pus," which is so abundant in man)' of the plaTlt^ 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 outward, brist- ling like the spokes of a small wheel. It is an interesting coincidence that this takes place simultaneously
. Elementary botany. Botany. SEED DISPERSAL. 461 1' .( thus exposed. The dark brown achenes stand over tlie surface of the recep- tacle, each one tipped with the long slender beak of the ovary. The â ⢠pap- pus," which is so abundant in man)' of the plaTlt^ 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 outward, brist- ling like the spokes of a small 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 thus broughtto 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 slo-\\'ly 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 embr)-o to comc in contact with the Fig. 433- 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
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