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punctate, cicatricules, of which the middle represents the cross 
section of the median nerve of the leaf the two lateral cicatricules 
(parichnos) corresponding to the passage of the lacunose parenchy- 
matous tracts, which originate in the inner cortex and communicate 
by way of the parichnos with the stomatiferous zones of the leaf. 
On either side of the lower angle of the leaf scar and contiguous to 
the latter there are, in most species of the genus, two small oval 
imprints, sometimes called appendages. 
These, according to Potonié, are poinls at which the lacunose 
transpiratory tissue comes in contact with the epidermis which is 
here, perhaps, hardly more than a membrane apparently ruptured 
in most instances. Just above the leaf cushion is indented by a 
small pit which is found to cotain a ligule homologous with that 
‘of the living Selaginella. 
The leaves of Lepidodendron are sometimes long, slender, and 
grass-like, thougt rigid ; at other short, small, and curved like those 
of various living coniferous genera. They are marked by the impres- 
sion of the nerve trace, or midrib, which is carinate on the dorsal 
surface ; and, at a little distance on either side of the midrib, by a 
narrow longitudinal dorsal furrow which contains the stomata. 
The fructification of LZepidodendron consists of more or less 
elongated cones or strobili known as Lepidostrobus. The spores, 
both microspores and megaspores, are contained in thinwalled spo- 
rangia, each of which is longitudinally attached alone the narrowed 
base of one of the spirally arranged and imbricated bracts or scales. 
Without the external characters of the leaf cushion and _ leaf 
scars it is impossible, in most cases, to determine the species of 
Lepidodendron. 
Where the epidermis and leaf scar are wanting, but the su- 
bjacent or spongy tissue of the bolster remains, the fossil is some- 
times known as Bergeria, or if but little of the spongy tissue is left, 
Aspidaria. When the cortex is largely removed the condition of pre- 
servation often is that described as AKnorria. The Lepidodendra were 
cosmopolitan in their distribution and range in the Northern flora, 
from the lower Devonian into the lower Permian. In the southern Per- 
mo-Carboniferous flora it is definitely represented only from Argen- 
tina and Brazil, though there have been records, subject to question, 
of the genus from the Karoo series, in South Africa. 
