316 FIRST FORMS OF VEGETATION. 
case touched, than it becomes suddenly inverted, 
and shoots forth, with a jerk, a little pellucid ball 
to a distance of upwards of three feet. This ball 
or sporangium contains the seeds, and is ejected 
with a force which, considering the nature and 
diminutive size of the plant, far exceeds that 
employed in the projection of a shell from the 
largest mortar, or a cannon-ball from an Arm- 
strong gun. It is a far more curious and interest- 
Fic. 30.—SPHAROBOLUS STELLATUS. 
Natural size, and magnified. 
ing object than the squirting cucumber. Another 
denizen of the hot-bed (Pegdga vesiculosa) exhibits 
somewhat similar properties. When the sun is 
shining warmly upon its cup, the least agitation 
raises a visible cloud of sporidia like a thin wreath 
of vapour. These are beautiful instances of the 
adaptations, with which nature has provided these 
lowly plants, for the certain dissemination of their 
ceed 
