288 
Kisch . — The Physiological Anatomy of 
In Bothrodendron the periderm arises immediately within the radial 
primary cortex. 
(f) Development. 
The first beginnings of the phellogen may be seen in a few of the 
Text-fig. i. Diagrammatic transverse sections to show first beginnings of periderm formation. 
A, Lepidodendron selaginoides. Will. Coll., 342. x 9. B, Lepidodendron sp. The developing 
periderm, pd , is shown in black ; st, stele; x 2 , secondary wood. Will. Coll., 1922 E. x 5. 
younger specimens. It develops in detached areas round the stem, but not, 
as described by Williamson 1 and Hovelacque , 2 in regular arcs under each 
1 Williamson ( 41 ), p. 286, PL XLVII, Fig. 1. In the specimen figured the periderm really 
extends all round the stem, but is more strongly developed under the leaf- bases, 
2 Hovelacque ( 15 ), p, 158, 
