| Show I SPREADING SEEDS 1 mature methods ethoda il of securing fertile seeds I 1 1 in good soil SH the methods by which seeds are di distributed is tri buted are most curious and inhere interesting st says knowledge the legume of the pea splits along its two margins the two halves falling away from each other and throwing off the seeds 17 in i various directions the seed cas cases eso of f the pansy and the violet explode scattering the seeds forcibly in the gorse and the broom a sudden burst of the pods and a spring like twist of their two halves effectually disperse the contents on sunny july days the cracking sounds produced by the bursting peri carps may be distinctly heard the mature fruit of elaterium separates from its stock and ejects its seeds with great rapidity through the orifice left by the rupture the sporangia of many ferns bracken have an elastic ring which is probably intended for the energetic dispersal of the s spores pores in certain pines the scales of the cone when thoroughly dried by the hot days of the summer following that of its production open with a jerk forcibly ejecting the winged seeds frequently a number will burotto burst together and then the sound may be heard card at a great distance in the expel expulsion ision of the seeds of the balsam impatiens the contact of some outside object is of advantage the seed case consists cofone of one cell with five valves and it if touched by accident when ripe it at once bursts open the valves coiling themselves vi violently 0 bently and springing from the stalk scatter the seeds in all directions I 1 in the poppy and snapdragon a still larger share of the work of releasing the seeds falls to au an outer agency for here the consists of a capsule which opens along the top by valves that reave leave small pores through which the seeds fall out when the capsules are shaken by the wind in all of these various methods of the expulsion of seeds it would seem that they are due to mechanical causes and depend in most instances im impatient 5 PS ex cepter upon a certain condition of dryness in themselves and upon the state of the surrounding atmosphere ra passing asing from the modes in which dry fruits consisting of a number of seeds enveloped in tough peri carps effect dissemination bem in i apiou we have to consider next the means which obtain among dry fruits whose seeds are not collectively in a strong seed case idere too we find the forcible ejection of seeds those of the oat are scathe scattered re d with such energy that on a fine dry day the snapping thus caused is distinctly audible audibe but the most curious provision possessed by seeds of this class for self dissemination is the hygroscopic awn in the wild oat aleua dafna for example there are attached to the gl umelia a small leafy structure connected with the seed a spiral awn covered with humorous fine hairs and this awn has the power of expanding when moist and of contracting when dry |
