94 FLORA OF LOWER COAL MEASURES OF MISSOURL 



scales or scaly hairs, which raav generalh' be discovered even in some por- 

 tions of the most macerated specimens; by the more oblique, straighter, 

 fewer, and more even nerves, and by the rather more distant sori and the 

 smaller sporangia. From the form described by Lesquereux from Mazou 

 Creek, Illinois, and from other localities as '■'■Pecopteris villosa Brongn.?," to 

 which it is more closely related than tO' any other species, the Missouri 

 plant seems to diflPer by the less robust pinnae, the more decurrent pinnules, 

 and the more oblique nervation in the pinnatifid pinnules. The rachis in 

 the plant so common at Mazon Creek is rather more densely and conspicu- 

 ously punctate. The Lacoe collection contains examples from the Radstock 

 coal field and the Forest of Dean, in England, which seem hardly separable 

 from the forms identified by Lesquereux as ^'■Pecopteris villosa Brongn.?" 

 P. vestita differs from P. ciintoni by its smaller size, more acute lateral pinnae, 

 narrower and much more regular pinnules, not narrowed at the base, rather 

 closer and a little coarser nervation, and its small, acute sporangia. 



Localities. — Most common at Owen's coal bank, U. S. Nat. Mus., 5646, 

 6647, 5683, 5684, 5686, 5688, 6746, 5754, 5755, 5758, 5760, 5766, 5767, 

 5770, 5773, 6808, 5822: Hobbs's coal bank, U. S. Nat. Mus., 5746, 5748, 

 5753, 5765, 5769, 6771, 67731, 5774; Pitcher's bank, U. S. Nat. Mus., 

 5747, 5752, 6753, 5766!, 5759, 5761, 5762, 5763, 5768; Henry County, 

 Missouri, U. S. Nat. Mus., 5656, 6749, 6757. 



Pecopteris clintoni Lx. 

 PI. XXXIV; PI. XXXY, Fig. 4. 



1879. Pccoi)teris Clintoni Lesquereux, Coal Flora, Atlas, p. 8, pi. xlii, figs. 1-3, 3a, -i, 4a 



(non figs. 5, 5a-b); text, vol. 1 (1880), p. 251 (pars). 

 1879. CaUipteridium memhranaceum Lesquereux, Coal Flora, Atlas, p. 6, pi. xxvii, 



figs. 5, 5a (uon figs. 6, 7, 8); text, vol. i (1880), p. 172 (pars). 



Frond large, ti-i- or polypinnate; secondary (I) pinnae lanceolate or 

 linear-lanceolate, acute, lax, somewhat pohTnorphous, and provided near 

 the apex with confluent pinnatifid pinnules; rachis broad, lineate, flat, lax; 

 lateral pinna? alternate, open, at a right angle to the rachis at the base, 

 becoming oblique above, generally rather distant, sometimes close or con- 

 tiguous, in-egular, lax, flexuous, lanceolate, lineai'-lanceolate, the lower ones 

 often slender and acute, the upper ones more obtuse; pinnules alternate, 

 very open in the middle, generally close, often contiguous, decurrent, poly- 



