CH. VI] LIGNIER'S THEORIES 71 



On this view the Equisetales and Sphenophyllales are descended 

 from a common fern-hke ancestor^. Lignier recognised Psilo- 

 phyton as a primitive Vascular Cryptogam 2. In his chief contri- 

 bution to this subject^, which appeared in 1909, he elaborates 

 his views so as to cover the whole vegetable kingdom. From 

 aquatic Algal ancestors, he derives terrestrial Prohepatics, 

 giving rise to Bryophyta on the one hand and Prolycopods on 

 the other. From the latter are derived the Primofilices and 

 Lycopods. In the development of these two races*, two distinct 

 morphological tendencies are recognised by Lignier as at work : 



1. Phy]loideae : leaves originating from emergences of the thallus — 



Prolycopods, and Lycopods alone. 



2. Phyllineae: leaves originating from modified thalloid branches — 



Primofilices, and all Vascular Cryptogams except Lycopods, and 

 all Spermophyta. 



The former were ab initio microphyllous, the latter mega- 

 phyllous. The Sphenopsida or Articulatae are regarded as 

 derived from megaphyllous fern-like ancestors. The author also 

 proceeds to consider certain Spermophytes such as the Coniferae 

 which are microphyllous, but as we are not here concerned with 

 any group higher than the Vascular Cryptogams, these matters 

 need not detain us. 



From this view we should be inclined to dissent in several 

 particulars. We regard it as extremely unlikely that the Bryo- 

 phyta, using that term in the widest sense, had any connection 

 with the origin ' of Pteridophyta. We should agree rather with 

 Fritsch^, in deriving the Bryophyta independently from the 

 Algae but at a much later period than that with which we are 

 here concerned. Halle's Sporogonites (see p. 44), which we have 

 discussed, has not shaken our conclusions in this respect. 



On the other hand we are strongly in favour of accepting 

 Lignier's conceptions of the Phylloideae and Phyllineae, though 

 on somewhat different lines, but at the same time we dissent 

 from any notion of either a primitive fern or prolycopod ancestry 

 for the Sphenopsida and Pteropsida. 



1 Lignier (1903), p. 132. 2 j^^^ (1903), p. 95. 

 3 Ibid. (1909); see also Scott (1910). 



* Cf. Janchen (1911) who also separates the Lycopods from other 



Pteridophyta on phyletic grounds. ^ Fritsch (1916). 



