202 FORMATIONS AND GUILDS [Part II 



colour whose oecological significance, if existent, is not yet known. Simul- 

 taneously with the chlorophyll, the organs that are functionally connected 

 with it are reduced, in particular the leaf-surface, which in saprophytes is 

 still present only in the form of a small scale, the stomata, which have 

 quite disappeared in some species, the tracheal passages, whose place is 

 taken by a few narrow vessels and tracheids. The subterranean system, 

 in accordance with the reduced transpiration, is less developed than in 

 green plants, and in many cases assumes a coralloid appearance. Mycorhiza 

 is well developed in saprophytes. So far as we can apprehend, their 

 flowers do not essentially differ from those of their non-saprophytic allies ; 

 their colour frequently agrees with that of their vegetative organs. The 

 peculiarities of their seeds have not yet been oecologically explained. 

 They are very numerous, of minute size, and possess an undifferentiated 

 feebly developed embryo. 



Saprophytes, unlike lianes, and especially unlike epiphytes, are not con- 

 fined to certain definite climates, but, at least in their systematically lower 

 forms, appear in all climates, whilst the higher forms prefer damper climates 

 and chiefly inhabit shady places. Their larger forms appear principally in 

 forests, in which saprophytes constitute an essential, if only occasionally 

 a noticeable part of the vegetation. The most conspicuous and commonest 

 saprophytes in Europe are pileate fungi ; phanerogamic saprophytes are 

 much rarer. But a close investigation shows us at once that humus is 

 completely permeated by fine mycelial hyphae, and that all dead stems, 

 branches, and leaves nourish a rich thallophytic flora of saprophytes. 



The more the chlorophyll-apparatus is reduced in amount in licmisapro- 

 pJiytes the more do they approach in general structure true saprophytes. 

 Coralliorrhiza innata and Limodorum abortivum, two humicolous orchids 

 poor in chlorophyll, very much resemble holosaprophytes, owing to their 

 leaves being reduced to scales, the first also by its coral-like rootless rhizome 

 and the second by its violet colour. This violet colour is seen in a still 

 higher degree in Lecanorchis javanica, an orchid poor in chlorophyll, which 

 I observed in Java. The gentianaceous Obolaria virginica I may consider 

 as belonging to a lower step in the transition to a saprophytic mode of 

 life. I frequently found this pretty little plant on the deep humus of very 

 shady forests near Baltimore, and was struck with the fact that, differing 

 from other shade-plants, it possessed a succulent stem and very small 

 leaves. 



4. PARASITES. 



Parasites derive their nutriment partially or entirely from other living 

 organisms, either plants or animals. They share with saprophytes the 

 property of obtaining their carbon partially or entirely from organic com- 

 pounds, and they assimilate the carbon-dioxide of the air in correspondingly 



