EQUISETALES— C ALAMAEIE.E— ASTEROPHYLLITES. 1 55 



from an axis not parallel to the stem, narrow, somewhat ronnded or thick 

 in transection, with a strong midrib, which is striate, carinate on the iDack, 

 and marked on the inner surface by two parallel lines. Where the carbona- 

 ceous matter is removed from one of the specimens, broken contig-uously to 

 the nodal diaphragm, the leaves, which go out at an angle of about 45° 

 with the stem, seem to be united at the bases in a sheath a little over a mil- 

 limeter in width. 



The occurrence of Asteropliyllites lonfjifolius at the coal banks near 

 Clinton has already been recorded by Professor Lesquereux.^ But an 

 examination of the specimens from the same localities now in the collections 

 of the United States National Museum reveals several that were identified 

 as A. rigidus by the same author. It is clear that confusion exists as to the 

 distinction between these two species in our American material, and it 

 would seem that the differentiation was perhaps not always plain or consist- 

 ent in the descriptions or figures of the Old World specimens. All the 

 material in both the Museum and the Geological Survey collections from the 

 vicinity of Clinton, appears, in my judgment, like the example shown in 

 Fig. 4, PI. XLIX, to agree with the A. hngifolius as figured by Sternberg,^ 

 Sauveur,^ or Zeiller,* although there is a strong resemblance to the A. rigidus 

 illustrated by Lesquereux in the fourth volume of the reports of the 

 geological survey of Illinois, while there are some points in common with 

 the figures of Old World material. Ottokar Feistmantel, who gave more 

 attention than most authors to the species of Aster ophyUites, explains' that 

 A. rigidus is distinguished from A. hngifolius by the shorter internodes, the 

 joints not so swollen, the leaves generally shorter and slightly broader, 

 lying parallel to the stem, a short distance above their bases, and especially 

 characterized by a certain rigidity. Sternberg's type is represented" with 

 these characters, though the leaves in his Bruhmannia longifolia'^ are also 

 soon turned upward, parallel to the axis, and, to judge by his figure, are even 

 more rigid. Mr. Kidston refers the specimen illustrated by Schimper as 

 CalamostacJiys typica in fig. 1, pi xxiii, of the Atlas to the latter's "Traiti^," 



'Coal Flora, vol. iii, p. 879. 



= Versucli einer yiora der Vorwelt, vol. i, pi. Iviii, fig. 1. 



3 V^g. foss. terr. houill. Belgique, pi. Iviil, fig. 1. 



■■Fl. foas. bassln houill. Valenciennes, p. 374, p]. lix. fig. 3. 



^^Verst. bohm. Ablagerungen, vol. i, 1874, pp. 123-125. 



f' Verauch, vol. i, pi. xix, fig. 1. 



^Op. cit., vol. i, pi. Iviii, fig. 1. 



