By means of a high-speed photographic technique, the initial velocities of seeds were studied as they were expelled from the fruits of four Colorado dwarfmistletoes: Arceuthobium douglasii , A. campylopodum f. cyanocarpum , A. vaginatum f. cryptopodum , and A. americanum . Velocities of the seeds of the latter two species averaged 2600 centimeters per second and were significantly greater than those of the first two, which averaged 2200 centimeters per second. The initial velocity of 526 seeds of the four dwarfmistletoes averaged 2400 centimeters per second.