1046 
Benson.—New Observations on 
and M. Cornaille have published a note 1 on the Botryopteris type of leaf- 
trace in which they refer to a form which they call Botryopteris antiqua , 
‘ d’Esnost ’. Professor Bertrand kindly sent me a photograph of the 
transverse section of the petiole of this form, and states that Dr. Kidston 
identifies it with his species. In this photograph one of the two protoxylem 
groups is excellently preserved, and agrees in structure with the more 
detailed account I have given of the new specimens, but the other is not 
clearly shown. Professor Bertrand tells me that this form from Esnost has 
been known to him for many years and was known to Renault, but there 
were difficulties in diagnosing it as a species distinct from those of the 
Upper Carboniferous Rocks. The reasons for this difficulty I will refer to 
later (vide p. 1048). 
The early date and wide distribution of the species, its variable but 
simple anatomy, make it an interesting subject of investigation, and I have 
therefore thought the following observations worthy of record. 
II. General Morphology and Range of Variation. 
The plant consisted of a rhizome which in one region gave rise to 
numerous adventitious roots and was covered with uniseriate hairs. After 
a short interval the rhizome bore petiolar structures whose traces came off 
at a two-fifth phyllotaxy. Often after only two nodes the rhizome gave 
off more adventitious roots, which sometimes arose very close to a node. 
Hairs are not generally found except on the root-bearing part of the stem, 
but this may be an accident of preservation. The petioles varied not only 
in size but in character. The larger ones contained a diarch trace, the 
smaller only a monarch trace. The latter forms generally left the stem at 
the same level with a curious uninerved sheathing body, probably to be 
homologized with the so-called aphlebiae of the Zygopterideae. It will 
be treated of in a later section (vide § VI). 
The stem stele varies very much in size and constitution in different 
parts of the same plant. In the purely leaf-bearing zone the protoxylems 
are concentrated into one or two centres, but in the region of root formation 
there are many scattered and peripheral protoxylem elements, and the 
transverse section of the stem is increased in size. 
As in the later species of Botryopteris the large metaxylem elements 
of the petiole trace are porose, while the smaller elements and protoxylem 
show all intermediate phases from porose to reticulate. As a result, where 
no leaf-traces are being differentiated in the stem, it presents quite a different 
appearance from that at a node. (Cp. PI. LXXXI, Fig. 1, and PI. LXXXII, 
Fig. 13 a.) 
Lastly, the Botryopteridean sporangia which are associated with these 
1 C. E. Bertrand et F. Cornaille : Les caracteristiques de la trace foliaire botryopt< 5 ridienne, 
t. cl, note, p. 1019. Comptes rendus des Stances de TAcademie des Sciences, 1910. 
