1904.] 



KNOWLEDGE 



FUNGI AS LINKS IN THE CHAIN OF LIFE. 



I.— THE NATURE. HABITATS, AND DISTRIBU- 

 TION OF FUNGI. 



By G. Jl.vssEE. 



Fuxr.t iiulnde the mushrooms ami to.ulstools, as well as 

 moulds, mildews, trutHos, puff-balls and yeasts, and 

 number altogether between fifty and sixty thousand 

 different kinds. 



It is only by eomparins: thoir modi' of life with that of 

 other groups of plants that tiie true nature of fungi and 

 their special chanicteristios can be clearly understood. 

 Flowering plants, ferns, mosses, seaweeds and lichens, in 

 fact all plants with the exception of fungi, possess 

 chlorv>phyll ; owing to the action of which they are enabled 

 to use c-arbonic acid and other inorganic substances as 

 food. Now the absence of chlorophyll must be considered 

 as the most distinctive hall-mark of the fungi, and its 

 absence implies their inability to utilize inorganic sub- 

 stances as food. This feature places fungi on a par with 

 animals, inasmuch as both agree in requiring organic food. 

 This fact is obvious in the cuse of those fungi that develoji 

 as parasites on living plants, as the destructive rusts and 

 mildews on wheat, barley, and numerous other plants, both 

 wild and cultivated. Neither would anyone doubt the 

 statement in the case of fungi growing on, and consequi-ntly 

 obtaining their food from rotten wood or dead leaves. 

 The case is not at first sight so evident, where fungi, as 

 the common mushroom, spring directly from the ground ; 

 when it might be supposed that the fungus obtained 

 its food from the same source as the grass growing 

 around it. 



Careful examination, however, would reveal the fact that 

 the spawn of the mushroom derived its food from the 

 decaying portions of grass an<l humus present, and not 

 from the soil. It will be remembered that when mush- 

 rooms are cultivated artitieially, the spawn is placed in 

 manure, which is organic matter, although dead and more 

 or less decomposed, and is not to be compared to such 

 inorganic substances as carbonic acid, obtained from the 

 air, and certain salts derived from the soil, which furnish 

 the grass with its food. 



Now this condition of things naturally prevents the 

 fungi from being pioneers in the dispersal of plant-life 

 over the globe. Mosses, algae, and other simple forms of 

 chlorophyll-ljearing plants, requiring only moisture, air, 

 and soluble rock constituents as food, can manage to grow 

 in barren and hitherto lifeless regions, if their seeds happen 

 to l>e carried by wind or other agents. This is not so with 

 fungi, which, for the reasons already stated, require organic 

 focxl. 



There are no other fast lines between fungi and other 

 members of the Vegetable Kingdom, all other distinctions 

 being only differences of degree. Taking structure, we 

 find that the characteristic unit, a cell with a well-defined 

 wall or enclosing membrane, forms the groundwork of 

 fungi, exactly as m all other plants, only in fungi the com- 

 ponent cells are not differentiated into what are known as 

 vessels, cork-cells, bast, &c., as in the higher plants. The 

 reason for this absence of specialized structure in the 

 fungi is the comparative absence of division of labour in 

 these plants as compared with ferns and flowering 

 plants. 



To understand this point of difference it must be remem- 

 bered that in all except the very simplest of plants, which 

 often consist of a single microscopic cell, there is a well- 

 marked division into a vegetative and a reproductive stage; 



and even in the simple one-celled plants alluded to above, 

 the one cell constituting the individual spends the first 

 period of its existence as a vegetative, and tin' last part as 

 a reproductive body. 



By the vegetative portion is meant all structures and 

 work done for the welfare of the iudividual ; whereas the 

 reproductive phase is entirely for the pur|)o.S(' of pro- 

 ducing other individuals of the same kind, usually from 

 seeds. 



Now if we take an oak tree as an example of one of llie 

 chlorophyll-bearing jilants, the root, trunk, branches aud 

 leaves, in fact every part except the flowers an<l fruit, 

 belong to the vegetative stage, in other words all the parts 

 mentioned are necessary for the coutinuaucr of life m the 



'., * m '^ 





Fig. 1. — .A. typical Agaric or gill-bearing fungus (.■<</arici(.t//vs/ri>). 

 The part above the ground-line is the reproductive portion ; tile part 

 below is the vegetative portion. Natural size. The ligureon the right 

 shows two basidia bearing four spores each. Magnified .500 times. 



individual tree under consideration. As the oak lives for 

 many years, the division of labour, or different kimls of 

 work necessary to enable it to do so, are many aud varied. 

 Of primary impt)rtance is a special arrangement for 

 obtaining food from the air and the soil, converting the 

 same finally into parts of the tree, and enabling the food 

 to spread to every growing portion of the plant. Then, 

 again, certain portions of the structtu-e are told oft' for the 

 purpose of giving strength to the whole fabric, so that t he 

 tree can withstand the force of the elements. 



As there is a limit to the life of the oak tree, in common 

 with every other living organism, some provision is 

 necessary for the continuance of the same kind of tree in 

 the future. This necessity is provided for by the production 

 of flowers ; these in the case of the oak eventually give 

 origin to acorns, or seed, which in due course develop into 

 other oak trees. This represents the reproductive cycle of 

 the oak tree, and it will be remarked that, so far as volume 



