A small genus of herbaceous plants of rather large stature, having opposite whorled or alternate leaves and large yellow monoecious flower-heads. Kay-florets female, and disk-florets barren. Achenes large, flat, winged longitudinally, the latter sometimes toothed at the top, and representing the pappus. Natives of North America.

1. S. laciniatum (fig. 128). Compass Plant or Rosin-Weed. - The slender stems of this species rise to a height of 3 to 6 feet, surmounted by large flower-heads, yellow with a dark centre. It received the name of Compass Plant because it was supposed that the leaves invariably presented their surfaces due north and south; and the second trivial name was given to it on account of its resinous exudation. There are several other species, but they are rarely seen out of botanic gardens,

Fig. 128. Silphium laciniatum. (1/4 nat. size.)

Fig. 128. Silphium laciniatum. (1/4 nat. size.)