THE BOTANY OF A COAL MINE. 295 
densely covered with leaves ; and the scars left on the trunk 
after they perished give the beautiful markings by which the 
different species are distinguished. The leaves when found 
separately are called Lepidophylla. 
The fruit was a strobilus ( Lepidostrobus ) (pi. xvi. fig. 1) 
formed from a shortened branch, the leaves of which are 
converted into scales that support on their upper surface a 
single large sporangium (fig. 4), which appears to contain both 
macrospores (fig. 5) and microspores. 
These sporiferous strobili can scarcely be distinguished in 
general appearance and arrangement of parts from those of 
some recent Lycopodiacece , except in the great difference of 
size, but their containing two kinds of spores indicates an affi- 
nity rather with Rhizocarpece. 
Another cone (Flemingites, fig. 2), having the same external 
appearance, occurs in the coal measures though it has not yet 
been found connected with any supporting plant. Its sporangia 
(fig. 3) occur in enormous quantity in many coals, and the tree 
on which it was borne — probably one of the lepidendroid forms — 
must have been very abundant, and contributed largely to the 
formation of coal. It differed from Lepidodendron in having- 
numerous small sporangia supported on each scale. 
The structure of the stem also confirms the near affinity of 
'Lepidodendron to our living vascular cryptogams. In general 
arrangement of parts they agree indeed more with Gycadece , and 
thus appear to support the views of Dawson in regard to Sigil- 
laria , but the minute structure of the vascular tissue and the 
absence of medullary rays are much more important characters 
than the modifications in the arrangement of the constituent 
parts of the stem, which is often very different in the same 
order of plants. A comparison of the fossil arborescent trunk 
with the slender stem of a modern lycopod shows that the prin- 
cipal differences are the existence of a pseudo-medulla, and the 
arrangement of the vascular tissue as a solid cylinder in the 
fossil genus as against the central position and loose structure 
of the vascular tissue in the recent plant. In both the recent 
and fossil stems the vascular tissues are surrounded by a zone of 
thin walled cells, which has disappeared in all the dried speci- 
mens of Lycopodium I have examined, leaving the axis free, 
and which, as we have seen, is very rarely preserved in Lepido- 
dendron . 
Perhaps more genera have been established for the different 
parts of Catamites than for the fragments of any other fossil 
genus. The stem has been described as Catamites , Calamitea , 
and Catamodendron ; the foliage as Aster ophyllites, Annu- 
laria , Hippurites and Sphenophyllum , and the fruit as Volk 
mannia, Aphyllostachys , Huttonia , &c. 
