41 6 Scott. — On Peduncle of Cycadaceae. 
example, had in all respects the foliage of a Fern, and so 
had Heterangium^ ; in the latter the structure of the stem, 
apart from the secondary growth, is exactly that of a mono- 
stelic fern, while the supposed resemblance to Lycopodium 
is merely fanciful. Recent work has completely confirmed 
Williamson’s priginal view as to the Fern-affinities of these 
fossil genera. 
While the origin of the Cycadean stock — in the widest 
sense — from Filicineae is now well established, it is not 
possible in the present state of knowledge to determine 
more exactly the line of descent of our recent Cycadaceae. 
Though they retain many primitive characters, they form 
but one special group, of what was once an extensive 
and varied class, which we may call Cycadales. The best 
known of the abundant Cycadeoid remains which have 
come down to us from the Secondary Period, are those of 
Bennettiteae, a group very distinct from the living Cyca- 
daceae. Much additional palaeontological evidence will be 
required before the geological history of the latter family 
can be revealed. 
The Cycadales generally may even be polyphyletic, having 
perhaps sprung from the Filicineae at various points. The 
Lyginodendreae, Protopityeae, and Medulloseae all combine 
Filicinean with Cycadean characters, but they appear to join 
on to very different groups of Ferns. In the light of Count 
Solms-Laubach’s recent remarkable observations on the 
Cladoxyleae of the Culm 1 2 , it seems highly probable that the 
Medulloseae sprang from polystelic Ferns, each of the well- 
known rings of wood in the Medullosean stem corresponding 
to a distinct stele, with its own secondary zone. On the 
other hand, the Protopityeae 3 , and the Lyginodendreae, 
1 It is extremely probable that Sphempteris Honinghausi , Brongn. , was the 
foliage of Lyginodendron Oldhamium , and S. elegans , Brongn., that of Heterangium 
Grievii. Cf. Kidston, On the Fructification and Internal Structure of Carboni- 
ferous Ferns; Trans. Geol. Soc. Glasgow, Vol. ix, Pt. I. 
2 Pflanzenreste des Unterculm von Saalfeld, above cited. 
3 Solms-Laubach, Bot. Zeitung, 1894, Abth. I, p. 206. 
