November 2, 1891 ] 



KNOW^LEDGE. 



205 



spores of a ripe Mushroom as carefully as we may, none 

 of them will grow ; the first stage of the Mushroom's 

 existence must be passed in the body of an animal host, 

 and as horses, sheep, and oxen are all readily attracted by 

 its taste and mealy smell, it has never any difficulty in 

 finding a' host to take it in." Mr. Straton here takes it 

 for granted that the spores must pass through the body 

 of an animal such as the horse before germination will 

 take place, and he consequently adduces the pleasant smell 

 and taste of the Mushroom as attractive characters of 

 value to the plant. But has a short residence within an 

 animal host been proved to be a necessary probation to 

 germination ? I think not. It may or may not be the 

 case, however. The question is an interesting one, and 

 my remarks may, perhaps, elicit further information on 

 this point. Mr. M. C. Cooke, in an article on the 

 " Attractive Characters of Fungi,"'" does not evidently 

 give unqualified assent to the opinion expressed by the 

 writer just quoted. He states ; " Whether horses, oxen 

 and sheep really iid the common Mushroom we venture to 

 call in question, but they (Ui eat the grass upon which the 

 fungus spores have fallen." We have observed horses, 

 cattle and sheep eating the grass all around where Mush- 

 rooms have been growing, and seen them pass on, leaving 

 the Mushrooms for us to gather on our own account. This 

 does not show much animal predilection for fungus food, 

 and hardly bears out the paragraph that " horses, sheep 

 and oxen are readily attracted by the taste and mealy 

 smell." Without venturing to throw doubt upon the old 

 faith that the spores of the Mushroom are destined to pass 

 through the entrails of a horse, or that a horse or cow 

 may sometimes even eat a Mushroom if it comes in its 

 way, still we have great hesitation in accepting as an 

 article of beUef that they seek them out and devour them 

 bodily, for the sake of the preservation of the species." 

 Another writer maintains that msects, such as flies and 

 beetles, whose larva^ are often met with in decomposing 

 Mushrooms, are the active agents as much as horses and 

 oxen in develojjing the spores. He believes that a sus- 

 tained temperature may be necessary for their development, 

 and this they find in the bodies of these animals. Does 

 this not seem nearer the mark, than the statement that 

 during a period of its existence the Mushroom is a parasite 

 — that is, it feeds on the tissues or juices of a living host ? 

 The product of the germinated spore consists of a 

 number of tine threads, or hyphre, which unite to form the 

 spawn, or mycelium. The mycelial strands may some- 

 times attain the thickness of thin whipcord. They are 

 produced by a weaving together of the hyplial filaments. 

 Here and there small knobs appear on them, which develop 

 gradually into the Mushroom. The tissue of these is at 

 first continuous, but soon disintegration takes place, result- 

 ing in the formation of an annular cavity dividing the cir- 

 cumferential portion of the cap from the stalk. (Fig. I., 2, <■.) 

 Into this cavity down-growths of the cap make their 

 appearance and form the gills. The tissue of the gills is a 

 further development of that of the cap. The ends of the 

 filaments which border the gills are, as may be seen on 

 reference to Fig. II., at right angles to that of the trama. 

 In the trama the filaments arc not closely woven together; 

 while in the sub-hymcnial layer they are so closely 

 wci'ted that it appears as made up of small closely com- 

 pacted cells. Outside the sub-hymenial layer the ex- 

 tremities of the filaments form the basidia and paraphyses. 

 From the ends of the basidia the stalks, or sterigmata, 

 arise. A swelling sooner or later appears at the apex of 

 each sterigma, and this enlarges into a spore, which, 



• Xafvre, 20tli November, 1890. 



because it is produced on a basidium,^ is called a basidio- 

 spore. The spores contain the greater part of the proto- 

 plasm of the basidia. They soon acquire a thick coat, and 

 their connection with their parent becomes less and less 

 until at last they drop off as the purplish-brown bodies of 

 which we previously spoke. The life-history diagram- 

 matically represented -would be as follows : — 

 basidium 



/^ 



^. 



sporocarp (Mushroom basidiospores 



plant) (apogamy) ^ ^ 



myceUum 

 (spawn) 



The whole mass of the Mushroom is made up of the 

 wefted threads of enormously long and branched filaments, 

 which have been produced presumably from a single spore. 

 We have no evidence, however, against the assumption 

 that the mycelium on which a Mushroom arises has arisen 

 from more than one spore. The Mushroom has all its 

 parts developed some time before it is seen above gi'ound. 

 Its unexpected appearance there is doubtless consequent 

 on an increase in the size of its cells, and not on the 

 formation of new cells. " In .hidrirus n(l(iiin.-<," De Bary 

 says, " I succeeded in determining, by measurement of the 

 cells and counting their number on the transverse section, 

 that the increase in length and breadth of the stipe, which 

 becomes, on an average, 50 — 60 mm. long, from the time 

 when its length was about 3 mm., and its cells could be 

 exactly measured, must be almost exclusively due to an 

 extension of the cells." | 



During the primary stages of its growth, the cells on 

 the upper surface of the cap grow more rapidly than those 

 on the lower. The secondary period is marked by a more 

 rapid growth in the opposite direction, so that the margin 

 of the cap is brought further and further from the stalk. 



From what has been already indicated we can see that 

 the tissue of the Mushroom is not a true tissue, but such 

 as appertains to the lowest forms of plants — the Fungi. 

 The Mushroom, then, is a fungus. Its mode of life is 

 typical of that seen in the majority of the members of that 

 group. In its cells there is no green colouring matter 

 (chlorophyll), and in consequence it is unable to make use 

 of the carbon dioxide of the air as its source of carbon. It 

 relies upon other sources for it, finding it in the decaying 

 vegetable matter of the manure of sheep, horses, oxen, 

 &c. It assimilates the already elaborated carbonaceous 

 materials by the action of a ferment secreted at the tips of 

 the fibrils of its mycelium, and also takes up mineral 

 matters from the soil. 



The mycelium or spawn exists apparently for years 

 below ground, that is to say, it is perennial, while the 

 fructifications — the conspicuous Mushroom plants — are 

 transitory structures ; but as no one has observed the 

 germination of a spore, we are unable to say what time 

 must elapse between that act and the production of a 

 Mushroom plant. It is the spawn which absorbs the 

 nutrient material. Its etfect upon its surroundings is 

 sometimes seen in the production of " fairy rings," 

 although these are not so commonly formed by this 

 species as by some of its allies. The miraculous origin of 

 these rings has now been exploded ; poets must be content 

 with a less imaginative, although at the same time nioi-e 



t -V cell, from the end of which ii spore is produced in the manner 

 indicated, is called a basidium. 



J De Bary, " Comparative Morphology ami Biologv of the Fungi, 

 Mycetozoa, and Bacteria," page .^.'j. 



