The St. Johns herald., 1891-12-17
SPREADING SEEDS.
Natures Methods of Securing Fertile Seeds
 in Good Soil.

Natures Methods of Securing Fertile Seeds
 in Good Soil.
 The methods by which seeds are dis tributed are most curious and interest ing, says Knowledge. The legume of the pea splits along it's two margins, the two halves falling away from each other and throwing off the seeds in various directions. The seed cases of the pansy and the violet explode, scat tering the seeds forcibly.
 In the gorse and the broom a sudden burst of the pods and spring-like twist Of their two halves effectually disperse the contents. On sunny July days the cracking sounds produced by the burst ing pericarps may be distinctly heard. The mature fruit of Ecballium elater- ium separates from it's stock and ejects it's seeds with great rapidity through the orifice left by the rupture. The sporangia of many ferns (bracken) have an elastic ring, which is probably in- tended for the energetic dispersal of the spores. 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 jerk, forcibly ejecting the winged seeds. Frequently number will burst to- heard at great distance.
 Tn the expulsion of the seeds of the balsam Gmpatiens) the contact of some outside object is of advantage. The seed case consists of one cell with five valves, and, if touched by accident when ripe, it at once bursts open, the valves coiling themselves violently, and springing from the stalk, scatter the seeds in all directions. In the poppy and snapdragon a still larger share of the work of releasing the seeds falls to an outer agency, for here the pericarp consists of capsule which opens along the top by valves that 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 (impatiens eX- cepted) upon a certain condition of dry ness in themselves, and upon the state of the surrounding atmosphere.
 Passing from the modes in which dry fruits. consisting of a number of seeds enveloped in tough pericarps, effect dis semination, we have to consider next the means which obtain among dry fruits whose seeds are not collectively inclosed in strong seed case. Here too, we find the forcible ejection ot seeds. Those of the oat are scattered with such energy that on fine, dry day the snapping thus caused is distinctly audible.
 But the most curious provision pos sessed by seeds of this class for self dissemination is the hygroscopic avn. In the wild oat (aveua fatna), for eX- ample, there are attached to the glumelia Ia small, leafy structure con- nected with the seed), spiral avn cov- cred with humorous fine hairs, and this avn has the power of expanding when moist and of contracting when dry.
 Thus the attached seed is constantly on the move with the changes in the weather, the hairs clinging to any object met with, until germination or destruc- tion puts an end to it's motion.
 The seed of barley, too, is provided with similar avn, which is furnished with minute teeth that point toward it's apex. The seed, when lying on the ground, naturally expands with the moisture of the night and contracts with the dryness of the day, but, as the teeth prevent it's moving toward the point of the avn, all motion must be in the direction of the base of the seed, which will thus travel many feet from the parent stalk.