MALADIE ET SYMBIOSE 255 



maintien parait lie a 1'existence de ce singulier mode de vegetation des 

 champignons endophytes. 



Quite probably the respective fungi have preserved from the 

 happy days of ancestral Norm-Symbiosis, or at least of neighbourly 

 good relations with the ancestors of the orchids, sufficient 

 symbiotic apparatus and sufficient symbiotic sense still to incline 

 them to some integrity of growth under appropriate conditions 

 of mutuality. The fact that glycogen, i.e., a reserve product of 

 metabolism, useful for work, is sometimes found'in these clusters, 

 inclines me to the belief that the cluster formation has to do with 

 a gradual and specific exchange of substances between partners. 

 Such exchange may be facilitated by an extension of surface, 

 as by means of clusters, and this brings into operation the force 

 of surface-tension a force in virtue of which the physical proper- 

 ties of many substances may be altered. In effecting such 

 changes and lending themselves to the corresponding exchanges, 

 the fungi may well be thought of as rendering themselves useful 

 to the higher plants much in the same way as the Agriculturist, 

 by providing manure and general conditions, assists (symbio- 

 tically) our food plants. Nor, as in the above case, need the 

 respective processes depend upon physical attachment or upon 

 penetration of the orchid by the fungi. 



To what an extent the orchids have become " deracinees " in 

 the course of their reversal of Norm-Symbiosis, may be gleaned, 

 though probably but imperfectly, from Prof. Bernard's descrip- 

 tion of Bletilla hyacinthina, a very low exotic orchid, in which 

 there are nevertheless united, as he thinks : 



un ensemble de caracteres communs a toutes les Orchidees primitives en 

 general, tels que 1'habitat terrestre, le mode de vegetation sympodial, 

 la prefoliation convolutive, la position terminate des inflorescences, 

 1'independance des masses polliniques par rapport au rostellum. 



In the state of rest, such as one may behold in the plant in 

 December, Bletilla, we are told, is 



reduite a un rhizome articule, souvent ramifie, toujours vert et superficiel. 

 Chaque article du rhizome est constitue par un tubercule discoi'de montrant 

 les cicatrices circulaires de feuilles tombees et reli< a 1'article suivant par 

 une court e digitation horizontale ; la ou le rhizome se ramifie, un meme 

 article est relie par deux digitations a deux tubercules voisins. A 1'epoque 

 dont je parle, ce rhizome ne porte que des debris de racines plus ou moins 

 desorganisees et aucune ratine vivante. (Italics mine.) 



Yet (since the reversal of Norm-Symbiosis in this case has 

 probably not proceeded too far), what a startling amount of 



