248 FLOKA OF LOWER COAL MEASURES OF MISSOURI. 



at a very open angle, from the larger ones; nervation usually obscure but 

 often distinct in portions of the same leaf; nerves parallel, close, rounded, 

 numbering about 40 to the centimeter; e|)idermis marked with rows of 

 longitudinal cells or fine striae numbering about 18 to the millimeter. 



The fragments collected at Deepwater by Dr. Jenney, of the United 

 States Geological Survey, and by Dr. Britts, fiu'nish some interesting 

 details as to the supei-ficial characters of Tceniopliyllum, although the generic 

 type still remains unique and somewhat anomalous among Paleozoic plants. 

 The general form of the organism, as seen in a number of specimens, com- 

 prises a great number of streamer-like, rather delicate leaves whose decur- 

 rent and crowded bases cover and conceal a thick, somewhat rigid axis 

 several centimeters in diameter. On one large slab, which is 80 cm. long 

 and 48 cm. wide, there is near the left border a portion of a trunk or 

 branch about 5 cm. in diameter, its surface covered by the matted and car- 

 bonized compressed decurrent bases of the leaves, which pass off, nearly 

 parallel, to the right, becoming somewhat crinkled in the matrix, but 

 apparently as wide at the broken ends as at any point in the remaining 

 portions. Most of the leaves are large, some of the incomplete segments 

 being 30 cm. long and generally 15 to 17 mm. in width. Mingled with 

 these leaves are portions of small leaves somewhat irregularly disposed. 

 The general aspect of the segments of these organs, which for the sake of 

 convenience I shall call leaves, is better seen in PI. LXXI. This specimen 

 shows the usual A^ery thin pellicle of coaly residue, with its minute striation 

 or rows of cells, while here and there the rather fine nervation is visible to 

 the unaided eye, although it is more often scarcely to be distinguished with 

 a lens beneath the striated epidennis. 



Showing clearly tln-ough the compressed wall of the leaf is seen the 

 loose fascicle of parallel longitudinal vascular strands, about 2 or 3 mm. in 

 width, passing straight or with a sinuous course at various oblique angles 

 to the nervation. This fascicle or axis is seen in nearly all the leaves, and 

 branches pass from it into the smaller leaflets. It is clear that these lie in 

 the interior of the leaf. In their form and mode of occurrence ,they are 

 suggestive of the axis of the Stigmaria rootlet and may be the homologue 

 of the latter. Here and there on the leaves small umbilicoid or Stigma- 

 rioid cicatrices are found. They are never frequent, but are usually rather 

 distant, and, so far as I have observed, they are without a regular system 



