DIAGNOSIS OF OMPHALOPHLOIOS CYCLOSTIGMA. 337 
especially in the young or badly compressed branches, rhomboidal and acute, later- 
ally rounded, or squarrose-rhomboidal, or often reduced and truncated by com- 
pression, normally somewhat prominent, convex-protrusive, without caude or cor- 
rugation, marked near the apex by a punctate mammilla, and surmounted over or 
at a little distance above the middle by a large interior, more or less roundish or 
ovate-triangular, slightly concave, prominent boss, at the lower crest of which is 
situated a transverse cicatrix, probably the leaf scar. 
Central boss of the partially decorticated stem usually conspicuous, often appear- 
ing as an oval, slightly concave elevation, frequently apparently traversed by two 
somewhat indefinite vertical low ridges, and marked between the latter by a mi- 
-nute central trace; or, in the impressions, often appearing as convex and roundish 
or narrowed in either direction by the partial infolding of the surrounding tissue 
of the bolster in the course of compression. 
Foliar cicatrices situated at or a little below the sail of the bolster, and on the 
lower border of the Jarge boss or cushion, nearly one-half the width of the bolster, 
of very little altitude, slightly raised, angular or slightly crescentic below, the sides 
slightly upward inclined, sub-angular or broadly crescentic above, or flatly deltoid 
in the center, the lateral angles being continued for a distance as diminishing 
ridges which are either straight and vanishing short of the margin, or curving up- 
ward and blending with the base of the large central boss, within which, close 
above the foliar cicatrix, lies a smaller oval or slightly ovate boss containing an in- 
terior depression and punctiform trace. 
Oval boss situated upon the large boss close within the ventral curve of the leaf 
scar, the longer, vertical axis being nearly one-half the altitude of the concave 
field of the larger boss, the horizontal diameter nearly two-thirds as long as the 
vertical, the lower end generally obscure, nearly or quite tangent to the leaf cica- 
trix, or possibly joined thereto, partly or wholly inclosing a minute punctiform 
mammilla which appears nearly contiguous to the foliar cicatrix and may be a part 
of the latter. Interior of the oval boss occupied by an oval depression, sometimes 
obscure, usually clearly defined, about .5 millimeter within the outer border of the 
boss, the interval being a flat oval zone, the upper and deeper end of the depression 
containing a minute umbilicate bordered trace. Vascular trace of the leaf appar- 
ently well developed, the lateral traces being obscure. Basal appendages either ab- 
sent or very obscure. 
INTERPRETATION OF THE PARTS 
The difficult task of the interpretation of the details enumerated above 
and of the ascription to the structures of their appropriate functions is 
largely a matter of speculation and hypothetical analogy. I shall at- 
tempt only to prove some of the homologies between the trunk in hand 
and others of the Lepidodendroid type, hoping that other paleobotanists 
more familiar with the Lycopodinex, both living and fossil, will furnish 
more accurate and valuable correlations. 
The type of cortex before us appears to be one characterized superfi- 
cially by rather strongly protuberant, non-carinate bolsters, exhibiting 
in outline the general variations characteristic of the Lepidodendroid 
L—Butt. Grou. Soc. Am., Vou. 9, 1897 
