EQUISETALES—CALAMARIEyE— ANNUL AEIA. 157 



appearance of the bases of the iuternodes and the position occupied by 

 several fragments of sporangia, makes it seem probable that the specimen 

 belongs to the genus Palceostacliya Weiss As such, it might be compared 

 with P. jyechmculata Will, althougli the iuternodes are rather long for that 

 species. 



The inclusion of this fragment in the species bearing the above name is 

 made entirely in deference to the great knowledge and experience of 

 Professor Lesquereux, who seems to have identified it without question as 

 Calamostacliys ovalis. A comparison of the original figure^ with the later 

 figm-es^ published by him as this species shows two quite different plants; 

 and while the fragment in hand differs much from the specimens from the 

 Pottsville series illustrated in the Coal Flora, it agrees hardly better with 

 the figure of the early type, the internodes being almost twice as long. 

 The precise generic relationship of either of the illustrated plants is hardly 

 determinable from the figures. 



Locality. — The specimen comes from the vicinity of Clinton, Henry 

 County, Missouri, No. 8056 of the Lacoe collection, U. S. Nat. Mus. 



ANNULARIA Sternberg, 1823. 



Yersuch eiiier Flora der Yorwelt, vol. i, fasc. 2, p. 36. 



That certain among the Annulariseform types represent foliate parts of 

 some Calamites is now generally accepted, the case of Anniilaria ramosa hav- 

 ing been amply developed almost simultaneously by both Weiss and Stur. 

 The more recent researches of Dr. Potoni^ go far in showing the relations 

 of Annularia to both the Equisekim and Calamodendroid types. As the 

 result of his study of well-preserved material from the Rothliegende of Thiir- 

 ino-ia, Potoni^^ demonstrates that the leaves of A. stellata are joined at their 

 bases in a narrow, spreading sheath, comparable to Eqtdsetum, while theu- 

 superficial structure is in all respects essentially the same as that of the 

 leaves of Equisetites semformis (Schloth.) Andra and Calamites varians Stb. 

 Moreover, in certain verticils of Equisetites ^eaformis he finds the leaves 



' In Rogers : Geology of Pennsylvania, vol. ii, 1858, pi. i, fig. 2. 



2 Coal Flora, vol. iii, 1884, pi. Ixxxis, figs. 3, 4. 



■■^Der iiussere Ban der Blatter von Annularia stellata (Schlotheim) Wood mit Ausblicken anf 

 Equisetites zewformis (Schlotheim) Andrii und anf die Bliitter von Calamites varians Sternberg: Ber. 

 d. Deutscli. l)ot. Gesell., vol. x, 1882, p. 561-.5(i8. Die Flora dea Eothliegenden von Thilringen : Abh. d. 

 k. Preuss. geol. Landesanst., N. F., Hft. 9, Tb. ii, 1893, pp. 170, 179. 



