LEAVES AND CONES IN VERTICAL ROWS. 475 
the trunk and scars of some of these extraordi- 
nary Coniferae. 
Among existing vegetables, there are only a 
few succulent plants which present a similar dis- 
position of leaves, one exactly above another in 
parallel rows ; but in the fossil Flora of the Coal 
2. Favularia. Stem furrowed. Scars of leaves small, square, 
as broad as the ridges of the stem. 
3. Megaphyton. Stem not furrowed, dotted. Scars of leaves 
very large, of a horse shoe figure, much narrower than the 
ridges. 
4. Bothrodendron. Stem not furrowed, covered with dots. 
Scars of cones, obliquely oval. 
5. Ulodendron. Stem not furrowed, covered with rhomboidal 
marks. Scars of cones circular. 
In the three first genera of this group, the scars appear to have 
given origin to leaves ; in the two latter they indicate the inser- 
tion of large cones. 
In the genus Favularia (PI. 56, Fig. 7) the trunk was entirely 
covered with a mass of densely imbricated foliage, the bases of 
the leaves are nearly square, and the rows of leaves separated by 
intermediate grooves ; whilst in Sigillaria the leaves were placed 
more loosely, and at various intervals in various species. (Foss. 
Flora, PI. 73. 74. 75). 
In the genus Megaphyton the stem is not farrowed, and the 
leaf scars are very large, and resemble the form of horse shoes 
disposed in two vertical rows, one on each side of the trunk. 
The minor impressions resembling horse shoes, in the middle of 
these scars, appear to indicate the figure of the woody system of 
the leafstalk. (Foss. Flora, PI. 116, 117.) 
In the genus Bothrodendron (Foss. Flora, PI. 80, 81) and 
the genus Ulodendron, (Foss. Flora, PI. 5. 6.) the stems are 
marked with deep oval or circular concavities, which appear 
to have been made by the bases of large cones. These cavities 
are ranged in two vertical rows, on opposite sides of the trunk, 
and in some species are nearly five inches in diameter. (PI. 56. 
figs. 3. 4. 5. 6.) 
