Read it through once

Some plants make a sort of catapult to sling or hurl their fruits. Kerner von Marilaun was the first to describe some of these curious arrangements. He had brought home some fruits of _Dorycnium herbaceum_ and laid them on his writing-table. "Next day as I sat reading near the table, one of the seeds of the Dorycnium was suddenly jerked with great violence into my face." Some of the neatest catapult fruits are those of _Teucrium flavum_. (There is a British species, the Woodsage, but it has not got the same arrangement.) When the petals have fallen off, the four small fruits are left inside the cup-like sepals; the flower-stalk when dry is very elastic, and if an animal touches the sepals it swings violently and shoots out one of the fruits. But that is by no means the whole of the process: there are hairs arranged spirally in the throat of the sepals, and these give a spin or twirling motion like that of a rifle-bullet to the fruit. The fruit also flies out of the sepals in a line of flight which is inclined at an angle of about forty-five degrees to the horizon; at this angle, as is well known, the trajectory or distance travelled will be the greatest possible.