478 OPHIOGLOSSALES 



affected by disturbed nutrition. This may be presumed to have been the 

 case in Psilotum, where the large size of the synangium proportionally to 

 the small bifurcate leaf indicates reduction of the latter, but not of the 

 former in the same degree. 



In estimating the effect of mycorhiza in any family as a whole in which 

 it occurs it is necessary to take into account in the first place its constancy; 

 and it is seen that it is not constant in the Ophioglossaceae. Secondly, 

 it is a matter of general observation that plants with an endotrophic 

 mycorhiza commonly show a structure in accordance with a limited tran- 

 spiration stream : their root-system is compact, and hydathodes are absent 

 from their rather leathery foliage. 1 The Ophioglossaceae show such 

 structure, which should not be confused with the results of saprophytic 

 reduction. It may have been primitive for them, and in this connection 

 it is to be noted that mycorhiza has been described in plants from the 

 Lower Coal Measures, so that it is no newly adopted manner of life.'-' 

 The condition of Helminthostachys^ with its mycorhizal embryo and non- 

 mycorhizal mature plant, would be consistent with a primitive mycorhizal 

 state, from which the plant had broken loose and passed to an autotrophic 

 condition. But, thirdly, it is important to note that among plants at large 

 many species in which it is present show no sign of reduction either in 

 their vegetative or in their reproductive parts. This may be well illustrated 

 among the Pteridophytes themselves. Thus Lycopodiiim inundatum is found 

 to be mycorhizic, but its general habit, especially in the large American 

 forms, does not suggest reduction as compared with other species. 

 L. cernuum is mycorhizic in the young plant, but it is one of the most 

 elaborate of Lycopods. Selaginella spinulosa is mycorhizic, but 6". helvetica 

 is not ; and yet S. spiimlosa cannot be held as relatively reduced. How 

 little the occurrence of mycorhiza may be found to affect the morphological 

 character of Ferns is shown in the Marattiaceae. According to Kiihn 3 

 a fungus is found in the roots of Kaitlfussia, of Aniopteris, and of 

 Marattia alata, but not in those of Marattia fraxinea ; but no reduction 

 is to be noted as the result in the former Ferns as compared with the 

 latter. Again, Cyathea is stated to have mycorhiza, while Aspleniinn nidus 

 has not. 1 Such facts as these clearly indicate that in Pteridophytes the 

 presence of a mycorhiza does not spell reduction. Accordingly it cannot 

 be justly assumed that the somewhat inconstant occurrence of the mycorhizic 

 habit in the Ophioglossaceae has been a source of general reduction in the 

 family, though reduction may have played its part in certain species. The 

 argument in favour of their being a reduction series as a whole will have 

 to be based on other evidence. 



Pending the statement of such evidence, the Ophioglossaceae may be 

 treated, without any preconceived idea of general reduction, in the same 

 way as any other family of plants. The natural comparison of them 



1 Stahl, I.e. 2 Weiss, Ann. of Bot., xviii., p. 255. 



3 Flora, 1889, pp. 491-497. 4 | arise, I.e., p. 64. 



