THE HIGHER CRYPTOGAMIA. 263 



hand, Karsten" (' Vegetation sorgane cler Palmen,' Berlin, 

 1847, p. 125), called attention to the definite relation which 

 so often occurs between the ramifications of fern-stems 

 and the insertion of their leaves ; and Mettenius lately en- 

 deavoured ('Abhandl. K. Sachs. Ges. d. Wiss./ vol. vii,) 

 to show that no essential difference exists between the 

 mode of ramification of ferns and of the vascular crypto- 

 gams generally, and that of phaenogamous plants, inas- 

 much as the ramification of ferns owes its origin to the 

 development of lateral buds, which are normally situated 

 in a definite position with regard to the bases of the leaves. 

 Mettenius draws his conclusions from a number of species 

 of Trichomanes, whose lateral buds he considered to be un- 

 doubtedly situated in the axils of the fronds. He finds 

 even in Hymenophyllum instances of the transition between 

 axillary buds and buds springing from the fore side of 

 the stipes. With these he classes the Davallieae, which 

 exhibit transitions from axillary buds to buds which ori- 

 ginate in front of and underneath the axil. Mettenius 

 finds the buds of Plati/cerium cdcicorne and of many other 

 species behind and underneath the insertion of the fronds, 

 and in Polypodium vulgare (amongst others,) he finds the 

 bud so far removed from the point of insertion of its 

 own proper frond, that it appears to be opposite the next 

 older one. Mettenius considers these lateral buds to be 

 of the same nature as those found on the stipes of Pteris 

 aquilina and Aspidium filkc-mas, which I look upon as 

 adventitious buds distinct from the true ramifications of 

 the stem. He adopts Karsten's view, that in Dicksonia, 

 in consequence of a bud of this nature being developed at 

 an early period before the development of the frond be- 

 longing to it, the frond which originally belonged to the 

 stem is withdrawn from the latter, and transferred to the 

 apparently dichotomous ramification of the principal stem. 

 Mettenius also agrees with Karsten as to the mode of 

 branching of the stem of Pteris aquilina. 



If the object of this conception is to point out the 

 essential agreement between the ramification of the vas- 

 cular cryptogams and the axile position of the lateral 

 branches of pheenogams, it may be objected that the agree- 



