55 
The Botryopteridea. 
of pit are found in the simple water-conducting elements of the 
Pallavicinia-group of Liverworts, and it is not difficult to see how 
these mixed types could give rise to both the scalariform and the 
“ pitted ” type of tracheid. It must also be remembered that both 
types of pitting are sometimes found in one and the same tracheid 
among the Angiosperms, so that we must be somewhat cautious in 
attaching phylogenetic significance to this character. 
Fig. 1. Portions of two tracheids of “ Rachiopteris cylindrica ” showing 
intermediate forms between the “scalariform” and “pitted” conditions. 
Univ. Coll. Collection, K 15. X 450. 
In both genera the stem was upright and the organisation 
radial, the phyllotaxy being a fairly high spiral. The leaf-traces 
leave the stele as simple band-shaped strands, which in Gramma- 
topteris (Fig. 2) remain simple tangentially orientated bands in the 
Fig. 2. Grammatopteris Rigolotti. T.S. of stem showing solid stele, band¬ 
shaped” leaf-traces, and the bases of petioles with band-shaped vascular 
strands. After Renault. 
petiole, according to Renault’s figures, while in Tubicaulis (Fig. 3) 
they become C-shaped in cross section, but with the concavity of 
the C turned outwards, directly the reverse of the orientation typical 
of the modern ferns. We shall have to return to this peculiar 
orientation presently. 
We know practically nothing in either case of the type of 
frond or of the branching of the petiolar strand—information which 
would be of great interest—but assuming that the leaf-trace of 
Grammatopteris is correctly described, we may perhaps fairly regard 
