DESCRIPTION OF THE SPECIES. 251 



shaped and widened at the tips, whicli are imbricated, and have on their 

 ends a rounded rim marked with from three to seven furrows." 



Tiiis description agrees well with the appearance of a number of leafy 

 twigs found in the Potomac strata. 



TAXODiUiM (Glyptostrobus) ramosum, sp. nov. 



Plate CXXriI, Figs. 2, 3; Plate CXXIV, V\'i.2; Plato CXXVII, Ki};. 1 : Plato CXXXII, Tig. 1 ; Plate 



CLXVI, Fig. 1. 



Stems profusely l)rancliing at short intervals; branches short iind 

 rigid, often showing a tendency to a fastigiato arrrangement ; leaves on the 

 older twigs proportionally long, narrowly ellijitical, mostly appressed, 

 especially on the upper and lower faces of the twigs, the lateral ones some- 

 times slightly divergent at the tips and incurved; the leaves on the younger 

 stems short, narrowly elliptical, thick, and close appressed, strongly convex, 

 and keeled on the back; male aments on the tips of short branches not 

 seen; nerves single and thread like. 



Locality: 72d mile-post, near Brooke; very common. 



This plant is one of the most conmion conifers at the 72d mile-post. 

 The ultimate twigs often show at their tips a whorl of short, scale-like, 

 divergent leaves, that seem to have surrounded the base of the male aments. 

 These in all cases had fallen off, and hence their character could not be 

 made out. Tlun'c is little doubt, however, that some of the mmierous 

 aments of conifers from this locality, described as aments of conifers (a), 

 (h), (c), (d), come from this plant. Some of the forms of this plant are 

 a good deal like Wi(hbiii(jtoiiia Beichii, as figured by Velenovsky,* and 

 they also resemble the branches of Taxodiam {^Gljiptostrobus) expansum, but 

 differs from both of these in the strong convexity of the leaves on the 

 young twigs and their short, elliptical shape, as well as in being more 

 rigid, stouter, and nuich shorter in the twigs. The chief resemblance is 

 in the nerves, which in both Widdringtonia and in the Potomac plant 

 are single in each leaf, slender and thread-like, running along the mid- 

 dle of the leaves throughout their whole length. The ultimate twigs of 

 the Potomac plant are sometimes more delicate than in any of the forms 



■ Die GymuospermeD d«r buhiii. Kreideformation, PI. X, et seq. 



