HOW PLANTS ARE SCATTERED STT 
the structure of the seeds themselves, sometimes to that 
of the fruit in which they are enclosed; the essential 
point is to have transportation to a long distance made 
as certain as possible, to avoid overcrowding. 
446. Explosive Fruits.—Some dry fruits burst open 
when ripe in such a way as to throw their seeds violently 
about. Interesting < 
studies may be made, 
in the proper season, 
of the fruits of the 
common blue violet, 
the pansy, the wild 
balsam, the garden 
balsam, the crane’s- 
bill, the herb Robert, 
the witch-hazel, the 
Jersey tea, and some 
other common plants. 
The capsule of the Fia. 266. — Fruits of Linden, with a Bract joined 
to the Peduncle and forming a Wing. 
tropical American 
sand-box tree bursts open when thoroughly dry with a noise 
like that of a pistol shot. 
447. Winged or Tufted Fruits and Seeds. — The fruits 
of the ash, box-elder, elm, maple (Fig. 169), and many 
other trees, are provided with an expanded membranous 
wing. Some seeds, as those of the catalpa and the trumpet- 
creeper, are similarly appendaged. The fruits of the 
dandelion, the thistle (Fig. 267), the fleabane, and many 
other plants of the group to which these belong, and the 
seeds of the willow, the milkweed (Fig. 267), the willow- 
herb, and other plants, bear a tuft of hairs. 
