271 
Dr. P. Bertrand on Zygopteridece. 
book. On the other hand the problematic genus Dineuron , Renault, of 
which a new species from Burntisland has recently been described 
by Mr. Kidston, is clearly shown by the author’s investigation to be 
allied to Clepsydropsis and Metaclepsydropsis. 
Chapter VII. gives a detailed and extremely useful statement of 
the taxonomy of the whole group, now including, as here defined, 11 
genera and 25 species. It is followed by a table (p. 225), indicating 
the probable affinities of the genera, and the supposed relations of 
the family to the Anachoropterideae and the Botryopterideae in the 
narrower sense. 
The author discards the ordinal name Botryopterideae in the 
wide sense in which it was used by Renault and has generally been 
adopted since ; he employs the name Inversicatenales (proposed by 
his father) to embrace the three families, Zygopterideae, Anachoro¬ 
pterideae and Botryopterideae (sensu stricto). The name is probably 
too technical to command general acceptance, for it is only in 
comparatively few cases that the foliar bundle actually shows an 
inverse curvature (i.e., with the convexity inwards). 
Part IV. discusses the affinities of the Zygopterideae with other 
families, beginning with the groups included under the order 
Inversicatenales. The author states incidentally that the stem 
referred by Renault to Anachoropteris Decaisnei is really a specimen 
of Ankyropteris scandens (Stenzel), the association of the stem with 
an Anachoropteris petiole being accidental (p. 227). He regards the 
Anachoropterideae as probably derived from a Zygopteroid type 
intermediate between Clepsydropsis and Dineuron, while the 
Botryopterideae (sens, strict.) form a parallel series. As regards 
the latter family the author’s views appear to be based too exclu¬ 
sively on the study of the late species Botryopteris forensis ; it is a 
pity that the older and simpler forms, B. hirsuta (Williamson) and 
B. antiqua, Kidston, were not also taken into account, for, as Mr. 
Kidston says: “ There seems to be a tendency in the petiole trace 
to become more simple in form as traced back in geological 
time.” 1 The hypothesis that Botryopteris was derived from the 
Zygopterideae is, however, interesting and tenable, though far from 
being established. 
The next chapter compares the frond-structure of the Zygo¬ 
pterideae with that of recent Ferns, as interpreted by the Bertrands 
and M. Cornaille. The detailed comparison confirms the position 
1 Kidston. On a new species of Dincuron and of Botryopteris from 
Pettycur, Fife. Trans. Royal Soc., Edinburgh. Vol. XLVI., 
Part 11., p. 364, 1908. 
