CHAMBERS'S INFORMATION FOR THE PEOPLE. 



fertilises it. This cell divides, and is soon developed 

 into an embryo, with a bud above and a radicle 

 below ; and then the circinate fronds shewing the 

 genuine fern-structure arise. As an order, ferns 

 are very widely distributed, generally consisting 

 of a number of leaf-like members called fronds, 

 which are the only visible portion of the plant. 

 In some species, however, the stem rises above 

 ground to the height of thirty to sixty feet, forming 

 the well-known tree-ferns of New Zealand and 

 tropical islands. 



Fern Allies. In the horse-tails (Equisetacece) of 

 our marshes and ditches, the spores are placed on 

 bracteated spikes, terminating the stems. Each 

 spore is furnished with two elastic filaments, which 

 are coiled around it, and are very hygrometric. 

 The horse-tails are herbaceous perennial plants, 

 having hollow striated stems, these being either 

 simple or branched. In point of size, they are 

 now insignificant members of the vegetable king- 

 dom ; but geology has revealed the gigantic pro- 

 portions they bore in ages long past, when, instead 

 of slender stems of a foot or two high, they reared 

 their gigantic pillar-like trunks to a height of 

 twenty or thirty feet. 

 The spores of the pill- 

 worts (Marsileacecz) are 

 inclosed in little ball- 

 like receptacles at the 

 bases of the leaves (see 

 fig.); the club-mosses 

 ( Lycopodiacea ) have 

 little cone-like spikes 

 at the tips of their 

 branches, between the 



scales of which occur small spores, while large 

 ones occupy the axils of the leaves lower down. 



In the true mosses (Musci], the spores are 

 inclosed in urn-shaped capsules, which generally 

 stand out from the leaves on slender hair-like 

 stalks. In the livenvorts and lichens there is a 

 somewhat similar provision ; and in the algae (sea- 

 weeds), the spores are often inclosed in the sub- 

 stance of the plant 



The fungi, or mushroom tribe, are extremely 

 diversified in their size, shape, colour, and con- 

 sistence. They are entirely composed of cellular 

 tissue. The common field-mushroom is one of 

 the best known, and may be cited as typical 

 of the family ; but the mould on cheese, stale 

 bread, the mildew on vines, the rust and smut on 

 corn, and many other minute and yet unobserved 

 appearances of a similar nature, are all fungi. 

 Their organs of reproduction consist of spores 

 variously arranged in different tribes, presenting 

 resemblances in some to the lichens, and in others 

 to algae. 



There is still much to learn respecting the 

 cryptogamic orders, which yearly receive increas- 

 ing accessions of students, for it is in these plants 

 that the whole vital phenomena of vegetation can 

 best be studied. ' We are entirely ignorant,' says 

 Professor Lindley, ' of the manner in which the 

 stems of those that are arborescent are developed, 

 and of the course taken by their ascending and 

 descending sap if indeed in them there really 

 exist currents similar to those of flowering-plants ; 

 which may be doubted. We know not in what 

 way the fertilising principle is communicated to 

 the sporules or reproductive grains ; the use of the 

 different kinds of reproductive matter found in 



76 



most tribes is entirely concealed from us. It is 

 even suspected that some of the simplest forms 

 of algae and fungi, at least are the creatures of 

 spontaneous growth : and, in fine, we seem to 

 have discovered little that is positive about the 

 vital functions of those plants, except that they 

 are reproduced by their sporules, which differ 

 from seeds, in germinating from any part of their 

 surface, instead of from two invariable points.' 



General Economy of Flowerless Plants. Insig- 

 nificant and lowly as the cryptogamia may appear 

 to the eye of the common observer, they are 

 nevertheless important auxiliaries in the opera- 

 tions of nature. It is true that man and his works 

 may suffer from their ravages, that mildew, rust in 

 corn, and other microscopic forms of vegetation, 

 by their rapid increase and destructive effects on 

 the substances from which they spring, may cause 

 incalculable damage ; but this very scourge pro- 

 vides an incentive to intelligent prevention and 

 care, while in creation there are no more useful 

 scavengers of decaying matter than the fungi. 

 In a dry season, for example, and on a favourable 

 soil, rust rarely makes its appearance : certain 

 conditions are necessary for its development ; and 

 it is to obviating these that the farmer must look 

 for exemption from this destructive malady in his 

 crops. 



It will now be understood that mould is a 

 fungus, produced by a previous deposit of germs 

 in the tissue or on the surface of the object on 

 which it grows. The proximate cause of its devel- 

 opment is generally damp, and without this con- 

 dition, the embryo remains in a dormant state. 

 Still it may be asked, how cheese happens to have 

 green mould at its very centre ? the reply is, that 

 the germs floating in the atmosphere had various 

 opportunities of rinding admission into this article 

 of diet. They may have been deposited on the 

 grass of a field ; the grass was eaten by the cow, 

 and the germs were so lodged in the milk ; or, 

 what is more probable, the gerrns fell upon the 

 curd, and there lay concealed till a certain damp- 

 ness in the cheese brought their vegetative powers 

 into operation. It is well known that the exposure 

 of curd for a day to the atmosphere will have the 

 effect of producing cheese liable to mould. A 

 fully more surprising instance of fungus vegetation 

 in a secluded situation, is that which occurs in the 

 fermenting of yeast and other substances. Fer- 

 mentation is, in one respect, a chemical process, 

 forming a first step towards dissolution ; but the 

 action is also vegetative. The whole mass of 

 matter gradually assumes the condition of active 

 vegetative growth. The fungus germs which had 

 been incorporated in the material begin to live 

 and expand, each being a plant which grows and 

 gives rise to new plants of the same species, until 

 the entire fermenting principle is exhausted. 



One great object which nature has in view by 

 the germination and dispersion of the algae, mosses, 

 and lichens, is clearly that of preparing the way 

 for a higher order of vegetation. It cannot pos- 

 sibly escape our observation that the tendency to 

 vegetate is a power restless and perpetual. We 

 hew a stone from the quany, and place it in a 

 damp situation, on the ground or in a wall, and 

 shortly a green hue begins to creep over it. This 

 is the commencement of a vegetable growth, pro- 

 duced by germs floated in the atmosphere ; which, 

 being attached at random to the stone, have been 



