— 075 — 
Dadoxylon Pedroi Zeill. 
1895. Dadoxylon Pedroi Zeiller, Comptes Rendus, vol. 
exxi, p. 964; Bull. Socc. géol. Fr., (3) vol. xxiii. 1896, p. 619, 
figs. 8-19, pl. ix, fig. 4: Arber, The Glossopteris Flora, 1905, 
p. 199. 
Pith very large, without chambers, cylundrical, tri-radiate in 
continous narrow, rounded, equidistant keels or generative ridges, 
along the surface of which the wedges of wood stand at right angles, 
and from which it is probable that branches and leaves had their 
origin. The pithis further characterized by the presence, scattered 
in its interior, of groups of 2-15 secretory cells, in contact with 
which the parenchymatous cells are narrowed and elongated in a 
pseudo-sheath. The pith cells also elongate approaching the spiral 
vessels at the apices of the wylent wedges. The xylem growth ts 
exclusivelly centrifugal, in wedges of greatly varying width, begin- 
ning with spiral vessels and rapidly passing through annular or 
sealariform to the pitted tracheides which cxclusively compose the 
avylem after passing a very short distance from the apex of the 
wedge. These tracheides are long, slender, somewhat irregularly 
disposed, and are marked on their radial wails by one or sometimes 
two rows of areolate punctations, which are rarely distant from one 
another, but which are generally close and partially polygonal where 
ir contact, especially twohen in two rotos. The central pore is small 
and exactly round instead of oval or elliptical, and is sometimes 
eccentric. The medullary rays are very wide at first, but they ra- 
pidly narrow to a thickness of but a single cell, though here and 
there a cell divides vertically by fission. The rays are often of great 
altitude, sometimes reaching a height of 50 cells or more, while at 
other times they are but a single cell in height. The individual cells 
are 5-6 times as long as wide, generally subtending three to five 
tracheides, and they are about as broad as high, they are punctated 
wtth scattered small oblique elliptical pores in contact with the 
tracheides. 
The above description is drawn from the admirable aceount giveri 
by Professor Zeiller of the anotomical characters of this wood, from 
a specimen in the collection of the Countess d’Eu from the valley of 
