90 THE ROYAL SOCIETY OF CANADA 
Leaves.—The leaves of the first rank are thin, minutely striate, 
about one millimetre wide and one and a half to two inches (35-50 mm.) 
long, narrowly linear and flexible. Leaves on small branches are fewer 
and shorter, as in Asterophyllites and Annularia. 
Fruit.—A rather small macrostachya, found in the shales, with the 
stems and leaves of this species may be its fruit spike. This strobile 
is slender and elongate-cylindrical; the ranks or rows of fruiting scales or 
bracts, are small, verticillate, and the cushions are lance-oval and 
acutely pointed. 
The following are further details in regard to this species:—The 
largest stems that have been recognized are about 25 millimeters wide; 
they are striate longitudinally with fine striæ of which there are about 
two to one millimetre (or more exactly, 12 to 5 mm.); at the nodes in 
these large stems knobs or cicatrices are frequently found to which 
leaves or small branches have been attached; such knobs are about 
one millimetre apart. Stems of half of the width of those above described 
are more common; these are ten to twelve millimetres in width and 
may be fifteen centimetres, or more in length, and have nodes two to 
six centimetres apart. At these nodes small branches are frequently 
found and the complete circumference of the stem may have ten scars 
to which such branches or leaves have been attached. Detached parts 
of such stems may have branchlets or whorls of leaves at one and a 
half to, two centimetres apart. 
Certain branches not otherwise distinguishable from those of this 
species, are irregular in their division and show a tendency to abandon 
the verticillate plan of growth for an irregular dichotomy; yet others 
of these stems while they branch dichotomously have a row of nodular 
scars at the base of the branch on the stem. Some terminal branches 
carry at theimextremities whorls of a few small verticillate leaves. 
The leaves of this Arthrostigma are often found detached; they 
are narrow, linear, striated lengthwise, one millimetre wide and about 
35-50 millimetres long, and are sharply pointed. They are distinguish- 
able from the young leaves of Himantophyton of the same size by the 
distinct longitudinal striation, visible only, however, with a lens. 
The striæ in this species run across the nodal line as in Archæo- 
calamites, but there are no ribs extending from node to node as in that 
genus and in Calamites. 
This species is much less abundant in the beds at Beaver harbour 
than Himantophyton, with which it is often freely intermingled. In 
its possession of both leaves and branches at the nodes it resembles 
Ramicalamus of the Dadoxylon sandstone; this latter however may 
have a number of whorls at the nodes; Arthrostigma differs also in its 
erect stem, which also is more slender. 
