MALADIE ET SYMBIOSE 257 



cotyledon ni radicule ; souvent il porte encore un suspenseur a sa maturite. 

 Le tegument de la graine est mince, reticule^ et d'ordinaire transparent. 



To judge even from the case of Bletilla, as depicted by Prof. 

 Bernard, the orchids at one time provided better for their progeny ; 

 they were, in my interpretation, better organisers, better workers, 

 better capitalists, and pari passii offered more resistance to fungal 

 penetration. They provided more albumen, more starch, more 

 sugar, more nectar, and, quite probably, all of it in higher quality 

 than now. The value of such substances, as we have seen, 

 largely depends upon their molecular constitution, and this, 

 in turn upon origin and nurture, and, hence, also upon associa- 

 tion and interaction. Bletilla, as a comparatively normal orchid, 

 does not yet present " les formes juveniles si particulieres des 

 Orchidees a protocorme," and it appears that "les caracteres 

 du premier developpement chez Bletilla hyacinthina sont des 

 vestiges, rarement conserves, d'un etat ancestral." And these 

 ancestral characters, we may feel sure, corresponded to a state 

 of higher biological integrity than is shown by the majority of 

 modern orchids. 



We cannot, therefore, make their present situation the 

 measure of that occupied by the orchids in earlier stages of their 

 history. At one time, no doubt, what they received by way of 

 " remuneration " for their biological services, differed in 

 character from what they receive to-day. Economic laws being 

 eternal, we may conclude that in " the good old times," with more 

 " patriarchal " integrity, the orchids reaped the fruits of " Norm- 

 rather than of " Luxury "- Symbiosis," and that they were 

 differently circumstanced accordingly. The fungi, for instance,, 

 we may infer, played a more subordinate role vis-d-vis to the 

 orchid ancestors than they do now. 



In order to facilitate an understanding of what is to follow, 

 it will be as well here to examine a little closer the question 

 regarding the predisposition to disease on the part of the Mono- 

 cotyledons. The phylogenetic origin of this class of plants may 

 be a matter of speculation, but if we consider their various 

 disabilities from the point of view of Bio-Economics, we may be 

 able to bring a little more discernment into the matter than has 

 hitherto prevailed and concurrently reach a better understanding 

 of the course taken by the orchids. 



In a very interesting paper on " Vegetable Degeneration " 

 (British Review, Oct., 1913), the Rev. Prof. George Henslow tells 



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