Dandelion (seeds)

1-20 inches. flowerhead 1/4 to 2 inches wide. (North American Wildlife, Reader Digest), "No weed is more successful than the dandelion. Its leaves exude an ethylene gas that discourages competition. A small fragment of it gluttonous taproot will grow into a new plant. Its parachute-borne fruits can stay afloat almost indefinitely as long as the humidity is less than 70 percent. Which means that when the humidity rises (often just before a life-giving rain), dandelion seeds come to earth.