GENERAL MORPHOLOGY 439 



and the three separate spikes ate inserted by sterile pedicels upon a 



common sterile stalk. Thus the branching, though less common, appears 



to be similar in kind to that in O. palmatum. 



Somewhat similar branchings, though less complete, are not uncommon 

 O. vulgatum. In the Kew Herbarium there are certain abnormal speci- 



icns which are of some interest in this connection. Fig. 239 j represents 

 plant of O. vulgatum taken in wet fields at Farnham, Surrey; from the 



ipper surface of the sterile frond arise three fertile spikes, one of which 

 branched, while the point of insertion of another is at some little distance 



rom the remaining two, which are seated close together. Though the 



letails of insertion are not identical, this may be compared with the Fig. 

 238 E of O. palmatum, or as regards insertion of the spikes with Fig. 238 D. 

 Another, and much larger specimen, showing a somewhat similar abnormality 

 of O. vulgatum, is seen in Fig. 239 K ; there are two leaves from the same 



)lant, each bearing three fertile spikes, which have, however, a common 

 insertion. Somewhat similar monstrosities are mentioned, as occurring 



irely, by Luerssen. 1 



In the Kew collection specimens of O. reticulatum also show abnor- 



lalities of a similar nature, though the branching is less complete : and 

 these specimens will serve to show that such abnormalities cannot be used 

 support the view that the fertile spike is a result of fusion of two 

 pinnae. One specimen from the Society Islands (Bidwell, Herb, Hook) 

 shows an equally bifurcated fertile spike, with a long sterile stalk : this 

 might appear to support the hypothesis of coalescence; but another speci- 

 men from Java (Lobb, Herb, Hook) shows three branches, of which the 

 central one is the strongest ; comparison should also be made of Figs. 239 

 j, K of abnormalities in O. vulgatum ; such cases as these would be entirely 

 inconsistent with the theory of coalescence as supported by abnormalities. 

 It must therefore be concluded from the genus, as we should already have 

 judged from the cases of O. palmatum and O. pendulum, that the forms 

 which the fertile spike occasionally assumes, gives no constant support to 

 the hypothesis of coalescence of lateral pinnae. This being so, and taking 

 also into account generally the facts of branching and insertion of the 

 fertile spike or spikes in the genus, the hypothesis that the fertile spikes 

 are of the nature of pinnae or leaf-segments appears to receive no consistent 

 support. On the other hand, all the facts are consistent with an hypothesis 

 of chorisis of a single original spike, holding a median adaxial position : 

 and it may be concluded that in Ophioglossum a fission, occasionally seen 

 in such species as O. vulgatum, has become habitual in O. palmatum, and 

 in less degree in O. pendulum. This is interesting for comparison with 

 what is seen in certain of the Sphenophyllales, where fission of the 

 sporangiophore appears to have occurred. 



But besides such probable amplifications within the genus, there is 

 also a line of probable simplification : it is seen in the new species, 



1 Rab. Krypt. Flora, vol. iii., p. 544. 



