COMPARATIVE DISCUSSION 477 



a general revision of the characters of the Ophioglossales has seemed 

 advisable; and^any such revision should involve not only their comparison 

 with other types, but also, what is perhaps more important, a comparison 

 of their different genera and species among themselves. 



The whole question of the character and relations of this family turns 

 upon whether they be regarded as an ascending or a descending series. 

 The former view, that they are a series of reduction, is entertained by many 

 botanists, but without, as far as I am aware, any full or detailed statement 

 of the grounds for this opinion : their " saprophytic habit " has, however, 

 been advanced as one source of their modification. 1 As regards this 

 saprophytic habit the following considerations may be brought forward. 



Mycorhiza has been observed in Ophioglossum vi//gaf/a/t.- in the mature 

 plant : Bruchmann states, however, that it is absent from the young plant. 1 ' 

 It is present in the mature plants of O. pendulum 4 and simplex? and is 

 specially prevalent in the peculiarly modified embryo of the former species 

 with its unusually precocious root. 1 ' It has been seen in twelve species 

 of Botrychiiim by Grevillius, but in varying abundance, 7 and Kiihn had 

 previously described it for B. Lunaria : s Bruchmann 9 showed that 

 mycorhiza is present in the young plant of the Moonwort, and that since 

 the eighth or ninth leaf is the first to be expanded above ground, 

 the plant is saprophytic in its nourishment up to its eighth or ninth 

 year. In Helminthostachys the fungus is present in the first three or four 

 roots of the young plant, but absent in the roots later produced. 1 " It is 

 thus seen that mycorhiza is not distributed with constancy in the family : 

 in some it may be present in the young plant but absent in the mature : 

 in others the converse; while some are distinctly saprophytic, none have gone 

 so far as to discard entirely the chlorophyll-function throughout life : in 

 Botrychium Lunaria, however, the mycorhizic habit appears to be obligatory. 11 

 The most peculiar case, as it is also instructive in another point, is 

 O. simplex, in which the presence of mycorhiza goes along with the 

 apparently complete absence of the sterile leaf; here it would seem that 

 the mycorhiza makes the nutrition of the large spike still possible in the 

 dense wet forest in which the plant grows, notwithstanding that the usual 

 assimilating organ is -functionally absent. Reduction is, however, not 

 apparent in the large spike itself, for provided nutrition be kept up from 

 whatever source, it would still retain its character, being essentially a spore- 

 bearing organ. Thus O. simplex teaches" what is also seen elsewhere, that 

 it is the vegetative rather than the propagative system which is primarily 



1 Scott, Studies in Fossil J-io/any, p. 511. - Kussow, 1'ergl, I'n/i-rs., p. 122. 



'Hot. Zeit., 1894, p. 241. 4 Janse, Ann. /ant. Unit., xiv.. p. 64. 



5 Bower, Ann. of Bot., xviii., p. 207. 



6 Campbell, I.e., Plate XVII., Fi.^s. 128, 129. 



7 Flora, 1895, p. 445. H Flora, 1889, p. 494. '' Flora, xcvi.. 226. 



'''Farmer, Ann. of Bot., xiii., p. 421, and Lang, Ann. of Bot., xvi., p. 42. 



11 Stahl, Prints. fahrb., xxxiv. , p. 574. 



