118 RELATIONS OF SAPROPHYTES TO THEIR NUTRIENT SUBSTRATUM. 



twenty-four hours, is certainly many times as great as that of the entire mycelium 

 which produced it; and it is quite incomprehensible how this mycelium, which for 

 weeks only achieves a moderate development, and adds but little to its dimensions, 

 is in a position suddenly, and in so short a time, to supply the amount of water and 

 organic compounds requisite for the building up of the fructification. Epipogium 

 aphyllum exhibits a similar property. After producing nothing for two years 

 excepting a few branches on its subterranean stem, it develops all at once and in 

 a very short space of time fleshy stems with large flowers, and one asks with 

 astonishment how the relatively small coral-shaped stock sets about obtaining the 

 quantity of nutrient materials necessary for the construction of these flowering 

 stems. We are here confronted again with the great mystery of periodicity, the 

 solution of which we must for the present forego. 



Saprophytes are much more fastidious as regards the quality of their nutriment 

 than one might expect. It is true that certain fungi are produced wherever there 

 are plants in a state of decomposition, and to them it is quite indifferent whether 

 the mouldered dust, which serves as a nutrient soil for their mycelia, has arisen 

 from one species or another. Also in the case of orchids imbedded in vegetable 

 mould, and in that of most of the mosses and liverworts adherent to the barks of 

 trees, it is, as a rule, of no consequence whether the tree constituting the substratum 

 is a conifer or a dicotyledon. But a large number of species are associated with the 

 decaying remains of particular plants or animals only. For example, certain small 

 species of Marasmius, belonging to the group of the Agarici, occur only on moulder- 

 ing pine-needles; another small fungus, Antennatula pinophila, is found exclusively 

 on fallen needles of the Silver Fir; Hypoderma Lauri, which resembles small black 

 type on rotting laurel leaves, and the tiny Septoria Menyanthis on leaves of the 

 Bog -bean (Menyanthes trifoliata) lying under water in a state of decay. The 

 cinnamon -coloured receptacles of Lenzites sepiaria only grow from prostrate 

 trunks of conifers, and the black fuliginous fructifications of Bulgaria polymoipha 

 only on those of oaks. A small discoid fungus named Poronia punctata, white 

 with black spots on the top, is only found on cow-dung; another fungus, Gymnoascus 

 uncinatus on that of mice, and Ctenomyces serratus on decaying goose feathers. 



That many mosses are also very fastidious in the selection of their substratum 

 has already been intimated. Just as in the Alps Splachnum ampullaceurn is only 

 found growing on the putrefying dung of cattle, so in arctic regions the splendid, 

 large-fruited Splachnum luteum and S. rubrwm occur exclusively on that of rein- 

 deer. Tetraplodon urceolatus is met with on mountains always with decaying 

 excrements of chamois, goats, or sheep for a substratum, whilst Tetraplodon 

 angustatus chooses the excrements of carnivorous animals, ami Tuyloria serrata 

 is only seen near cow-chalets on decomposing human faeces. The circumstances 

 of the occurrence of another moss belonging to the Splachnacese, i.e. Taylorla 

 Rudolfiana is also very interesting. It grows usually on the branches of old 

 trees, especially maples in sub-alpine regions, and one is temptctl to believe that in 

 respect of its nutrient substratum it is an exception to the rule of the rest of the 



