144 COMPENDIUM OF GENERAL BOTANY. 



to both saprcypliyte^i and jparasiUs. If the food-supplying organism 

 is alive and injuriously affected l)y such a relation, it is recognized 

 as jyarasitism. Vegetable parasites are either endophytic or epi- 

 phytic, that is, either growing witliin the })lant or attached to the 

 outer surface. If tlie organic substances Ijelong to dead organisms, 

 the organisms living ujjon them and taking nourishment from 

 them are known as saprophytes. Theoretically these groups may 

 be clearly separated, but actual obseiwation teaches that the two 

 modes of life-activity may become interchanged or may occur side 

 by side. 



Fungi are entirely dependent upon organic food, since they con- 

 tain no chlorophyll. In \\\^ numerous fungi which infect Hving 

 plants, but which can only reach their maxinuim development on 

 dead plants, parasitism and saprophytism seem to alternate. 



The few phanerogams devoid of chlorophyll are also dependent 

 upon assimilated or organic food ; for example, the orchid Epipo- 

 gon Gmelinii?, a saprophyte, Onscnta is a parasite; Monotrojm i& 

 said to be lK)th parasitic and saprophytic. Viscum alhuni^ the 

 well-known mistletoe, is evidently parasitic, although its green 

 leaves have the power of assimilation ; Neott'ia nidus avis is a sap- 

 rophyte and has some power of assimilation owing to the chloro- 

 phyll in the reduced scaly leaves. 



Parasitic ])hanerogams present remarkable anatomical arrange- 

 ments, which enable them to take up assimilated food-substances. 

 The details of this adaptive arrangement were studied by Solms- 

 Laubach, and L. Koch. There are three characteristic parts to 

 the organ which seiwes to absorb the food-substances; namely, 

 the haustorium., the sucTcer., and the absorhing-cells. These are 

 shown in figure 85, A and B. B represents the absorbing 

 cells, « tlie sucker somewhat magnified ; lu is the root of the h(jst- 

 plant. 



In regard to the parasitic fungi which have the power of pene- 

 trating cell-walls, it is to be noted that this phenomenon is associated 

 with the excretion of ferments having the property of dissolving 

 suberized as well as unsuberized cell- walls. To the Scldzomycetes 

 (bacteria) especially, various fermentative activities are ascribed, not 

 only for the purpose of dissolving cell-membranes but also for dis- 

 solving albuminous substances. The fact that chlorophyll -bearing 

 plants occur parasitically on rhizomes and roots of other plants 



