DISPERSION OF SEEDS. 25 



sooner is the ripening completed, than the capsule 

 becomes ahnost upright, with the calyx for a support. 

 This position appears to be intended by nature to give 

 more eflect to the valvular mechanism for scattering 

 the seeds, as the capsule thus gains a higher eleva- 

 tion (in some cases more than an inch) tiom which 

 to project them. Some ripe capsules of a line variety 

 of heart's-ease {Viola tricolor), which I placed in a 

 shallow pasteboard box, in a drawer, were found to 

 have projected their seeds to the distance of two feet. 

 From the elevation of a capsule, therefore, at the top 

 of a tall plant, these seeds might be projected twice 

 or thrice that distance.* 



We may mention, as another very curious illustra- 

 tion of the power in plants of discharging their seeds, 

 the remarkable instance of a minute fungus {Sphcero- 

 bolus stellahis, Tode). This plant has the property 

 of ejecting its seeds with great force and rapidity, 

 and with a loud cracking noise; and yet it is no big- 

 ger than a pin's head. I 



The circumstance alluded to as analogous in in- 

 sects to this admirable contrivance, occurs in the 

 forcible discharge of the eggs of some species to a 

 distance. The ghost moth {Hcpialus humuli), for 

 example, ejects its minute black egojs with so much 

 rapidity, that De Geer describes them as running 

 from the oviduct; and they are sometimes for- 

 cibly thrown out like pellets from a pop-gun. J 

 * A friend of mine,' says Kirby, ' who had observed 

 with attention the proceedings of a common crane- 

 fly (Tipula), assured me, that several females which 

 he caught projected their eggs to the distance of 

 more tlian ten inches. '§ Another instance is men- 



^- J. R. in Mag. of Nat. Hist., i. 380. 

 t For a minute account of this singular plant, see Grevill's 

 Scottish Cryptoganiic Flora, No. xxxii. 

 t De Geer, Mm. des Insects, iv, 494. 

 § Kirby and Speuce, Intr. iii, 66. 

 VOL. VI, fi 



