330 



FARMERS' REGISTER. 



[No. 6 



portions, termed cotyledons. When the young 

 plant, protrudes lioni the ground, it soniclinics 

 carries these cotyledons with it, as in the garden 

 bean, where they have the appearance of thick 

 fleshy leaves. The most remarkable i'act re- 

 specting the cotyledons is, tliat their number is 

 found always to correspond to the structure of tiie 

 plant which springs il'om them. The seeds of 

 plants with acrogcnous stems, such as feins, have 

 no discoverable albumen, and ol' course no cotyle- 

 dons. Hence such plants are called acotyledon- 

 ous plants. Those of plants having endogenous 

 stems, such as the Indian-corn, have but one 

 colyledon. Hence they are called monocotyle- 

 donous plants. Those ofplants having exogenous 

 stems, have always two or more cotylodons ; 

 hence these are termed dicotyledonous plants. The 

 division of the vegetable kingdom thus indicated, 

 forms the basis oi Jussieu's natural system of clas- 

 sification — the natural system in common use 

 among botanists at the present day. 



Besides the shell and the albumen, a rudi- 

 mentary plant, termed an embryo, always Ibrms 

 a part of the seed. This is the most important 

 j)art of the seed, and for its protection, and fulure 

 support, all the other parts are destined. The 

 embryo makes its first appearance in the young 

 seed, as a minute point or speck, in the midst oi' 

 the pulpy matter of which the seed then consists. 

 It afterwards gradually increases in size, derivinii 

 its nourishment from the pulp until it has assumed 

 the appearance of an organized body, and reached 

 its destined size. H;iving in itsehj in a rudimen- 

 tary stale, all the essential organs of vegetation, 

 viz., a root, stem, and leaves, it becomes a plant by 

 the mere developement ol its parts. When placed 

 in circumstances favorable to its growth, it sends 

 forth a root downwards, und astern upwards, and 

 lijeding for a time upon the stock of Ibod which 

 the parent plant has laid up lor it in the cotyledons, 

 it strengthens and gains a firtn foot-hold in the 

 earth, and at length becomes a perfect plant. 

 The embryo may be looked upon as a rudi- 

 mentary plant, provided by the parent tree, with a 

 certain stock of ibod, and thus Kent fijrih into the 

 world, to seek subsistence, and a home for itself 



Did the seed drop down from the plant on which 

 they grew, and immediately bury themselves in 

 the soil, great numbers would have to spring up 

 in close contact, so that if llicy did not destroy, 

 they would, at least, impede the growth of each 

 other. Tills, however, is seldom tlie case; there 

 is almost alwajs some provision made for re- 

 moving the seed from the immetiiate neighbor- 

 hood of the parent plant, and dispersing them 

 abroad in the earth. An examination of the 

 means made use of for elfecting this dispersion, 

 presents a subject of interesting consideration. In 

 some plants, the seed are contained in an elastic 

 pod, or pericarp, which opening, when ripe, with 

 a sudden jerk, scatters the seed to a considerable 

 distance. Of this the Scotch broom (^spariium 

 scopariu7n) aflords an examjile. During a dry 

 day in August or Scptend)cr its pods may be 

 heard snapping, at a very considerable diatance. 

 The wild touch-me-not (impaticns fulgida) af- 

 fords another example. If its seed-vessel be touch- 

 ed when ripe, it at once bursts, and the valves, coil- 

 ing themselves up, spring li-om the stem and scatter 

 the seed around. The bursting of the pericarps 

 of some species of pine, is also worthy of notice. 



The pericarp, which is a cone, remains on the tree 

 till the summer succeeding that during which it 

 was produced, the scales being still closed; but 

 when the hot weather has commenced and con- 

 tinued l(^)r some time, so as to dry the cone tho- 

 roughly, the scales open with a jerk, ejecting the 

 seed in every direction. But llie hura crepitans, 

 a plant of the West Indies, aftords the most re- 

 markable instance of this. "If the bony pod oi 

 this plant be bound with several folds of strong 

 cartridge paper, it will, so soon as it become tho- 

 roughly dry, burst with force sufhcient to tear this 

 paper in pieces." We observe a different means 

 of dispersion in the barley (hnrdeum.) "The awn 

 of the barley grain, which is beset with a multi- 

 tude of little teeth, all pointing towards its upper ex- 

 tremity, effects the movement of the grain away 

 fi'oni the place where it fell. For when tlie seed 

 with its awn falls from the ear, and lies flat upon 

 the ground, it is necessarily extended in its dimen- 

 sions b\' the moisture of the night, and contracted 

 by the drought of the day; but as the teeth pre- 

 vent its receding in the direction of the point, it ia 

 consequently made to advance in the direction of 

 the base of the seed, which in this way, is often 

 carried to the distance of many fi;et from the stalk 

 on which it grew. If an}' one is yet skeptical re- 

 specting the travelling capacity of the awn, let liim 

 only introduce an awn of barley, with the seed 

 uppermost, between his coat and shirtsleeve at 

 the wrist, when he walks out in the morning, and 

 by the time when he returns to breUidiisf, if he 

 has walked ar.y considerable distance, lie will find 

 it up at his shoulder. This journey has been ef- 

 fected by means of the continued motion of tlie 

 arm, and consequently of the teeth of the awn, 

 aclino; as feet to carry it forward." 



Where seed are to be dispersed to a great dis- 

 tance, nature makes use of the agency of winds, 

 streams, ocean currents, and living animals. The 

 agency of winds is one of the most efiiective of 

 these modes of dispersion, and in the case of many 

 seeds, we may notice in their structure, peculiari- 

 ties fitting them for being scattered in this way. 

 The seeds of mosses, lichens, and fungi, are so 

 exceedingly minute, that they float with ease in 

 the air, and veiretate wherever they meet with a 

 suitable soil. The seed of the white poplar (^liri- 

 odendron iuHpifcra) are flirnished with a wing, so 

 that v/hen failing fi'om the tree, they are caught by 

 the wind, and carried to some distance. The seed 

 of the maple (accr) and el.n (ulma) are fitted for 

 this mode of dispersion, by the structure of their 

 capsules, which are furnished with membrana- 

 ceous wings, and of course are aflected by the 

 wind, in the same way with the seeds of the white 

 |)oplar. The seeds of the dandelion (lenntodon 

 taraxacum) and thistle (cnicus lanccolatus) are 

 terminated by a slender stalk, supporting a tuft of 

 fine hairs at its extremity, 'i'his tuft of hairs is 

 eminently h^grometrical. spreading out in dry 

 weather, and collapsing again when the atmos- 

 phere is damp. In consequence of this spreading 

 of the hairs, so soon as the seed are ripe, they are 

 broken off from the stem, and thus the more easily 

 taken up and borne along by the wind ; but so soon 

 as a drop of rain strikes one of them, the tuft of 

 hairs immediately collapses, the seed falls to the 

 ground, and is imbedded in the soil, in circum- 

 stances the most favorable to its fulure growth. 

 The seed of the curly-head {clcviatis viurna) are 



