SELLARDS.] Fossil Plants, Upper Paleozoic, Kansas. 409 
em.; width 3 to 5 cm. The first ultimate pinna on the upper 
side above the base of the secondary pinna reduced, 3 to 5 cm. 
long, consisting in extreme cases of only two pinnules on each 
side and a large terminal pinnule, the first on the lower side 
somewhat reduced, springing from the angle made by the union | 
of the secondary with the primary pinna. Pinnules alternate, 
at right angles or inclined, rounded above the base to the point 
of attachment, more or less distinctly auricled below, auricle 
1 or 2 mm. long, free from the rachis, obtusely rounded, in 
aberrant individuals prolonged to 2 or 3 mm.; acutely pointed, 
often, especially in the ovate form of the pinnules, inconspicu- 
ous or entirely absent. Pinnules close, often touching or even 
overlapping, but sometimes more distant, more or less clearly 
distinct, markedly so in some of the higher Coal Measure forms, 
size and shape very variable, according to the position of the 
ultimate pinna on the frond and to a lesser extent according to 
the position of the pinnule on the ultimate pinna itself. The 
large pinnules reach an extreme length of 2 to 3 cm. and a 
width of 9 to 11 mm., sides nearly parallel, or sloping slightly 
to an obtuse apex; pinnules borne on pinnee higher up have a 
length of 13 to 15 mm. and a width of 7 to 8 mm., sides nearly 
parallel, or sloping a little to a very obtuse apex. The pin- 
nules become progressively smaller on the ultimate pinnz ap- 
proaching the apex of the secondary pinna, and ultimate pinnee 
may be found bearing pinnules from 7 to 9 mm. long and only 
4 to6 wide. The basal pinnule of each pinna is enlarged, pro- 
longed, often touching or lying across the rachis. Pinnules 
attached by a part of the base only, attachment 1 or 2 mm. 
wide; or by the entire decurrent base of the small pinnules at 
the top of the ultimate pinnee. The nerves are supplied by one 
strong strand at the center and several smaller ones on each 
side; the central strand is traceable in the smaller pinnules 
one-half the length of the pinnule or less, in the larger, one- 
half to two-thirds the length; thence by numerous dichotomies, 
and a strong outward curve the central strand supplies veins 
to the upper part of the pinnule. The thin veins at the side, 
by dichotomizing one to four times and spreading outward, 
supply veins to the base and auricle.' The veins are thin, fine, 
very numerous, counting 35 to 40 per centimeter at the border, 
deeply immersed in the thick and rather resistant epidermis. 
When the epidermis is removed the veins appear as very fine 
threads running through the lamina. 
