2 Seward . — On the genus Myeloxylon ( Brong .). 
In Corda’s great work, Flora der Vorwelt 1 (1845), a figure 
is given of a transverse section of a plant, from Radnitz in 
Bohemia, under the name of Palmacites carbonigerus. As 
the name implies, this was considered to be a Palm. In his 
description of the specimen Corda points out that much of 
the bundle-tissue has been destroyed, and the spaces filled 
with mineralizing material. In some places (Figs. 4 and 5, 
PI. XX.) sclerenchymatous elements are shown in close con- 
nection with the vascular bundles. The tracheids are 
described as scalariform : no mention is made of mucilage- 
canals, but in Fig. 5 Corda has represented what we may in 
all probability regard as such. This species of Palmacites 
bears a strong resemblance to Myeloxylon (. Myelopteris ) 
radiata. 
In 1832 Cotta 2 instituted three species of Medullosa\ 
M. elegans is the only one with which we are at present 
concerned. This species is recorded from Rothliegende 
(Permian) rocks near Chemnitz and Kohren. In the Robert 
Brown collection in the British Museum is a specimen which 
was no doubt cut from the same piece as the section figured 
by Cotta in PI. XII. Fig. 2 ; in this section a number of dark 
lines of crushed cells are seen in the parenchymatous ground- 
mass surrounding small ‘islands ’ of mineralized tissue. This 
mode of fossilization is fairly common in Myeloxylon and well 
marked in some of the examples to be described later. 
Brongniart 3 , in his Tableau des genres de vegdtaux 
fossiles, changes the name Medullosa to Myeloxylon , and 
classes Myeloxylon elegans as a doubtful Monocotyledon. 
Goeppert 4 describes the hypodermal tissue of Myeloxylon as 
wood ; he considers the dark lines in the ground-tissue as part 
of the natural structure of the plant and not as an accident of 
1 Corda, Beitrage zur Flora der Vorwelt, PI. XIX. Fig. 2. 
2 Cotta, Die Dendrolithen, PL XII. Figs. 1 and 2. 
3 Brongniart, A., Tableau des genres de vegetaux fossiles, consideres sous le 
point de vue de leur classification botanique et de leur distribution geologique 
(Dictionnaire universel d’Histoire Naturelle, vol. XIII. p. 59 [1849]). 
4 Goeppert, Die fossile Flora der Permischen Formation, p. 218 (Palaeonto- 
graphica, XII. 1864-1865). 
