22 ARKIV FÖR BOTANIK. BAND 13. NIO 7. 



The resemblance lies especially in the habit, at least the 

 smaller specimens of Zigno's (1. c, pi, 3, figs. 2, 4, 5; pi. 4, 

 figs. 1 — 3) being very similar to the Swedish ones, Zigno's 

 description and the enlarged drawing in his pi. 3, fig. 4, 

 however, show a considerable difference: the Italian form 

 has the free teeth shorter and more abruptly and bluntly 

 pointed. E. Lyelli, a well-known species of the Wealden, has 

 teeth of very much the same shape as E. Mohergii, but it is 

 generally considerably larger, with longer and more numerous 

 teeth. The resemblance is a very close one, however, and 

 it would appear as if E. Lyelli was the species most closely 

 related to E. Mohergii. 



There are in the collection a couple of disc-like bodies 

 which no doubt represent diaphragms of this species. One 

 of them is shown in our pi. 2, fig. 23. It is rather large, 

 about 10 mm. in diameter, with a thin marginal zone. In 

 the centre there is a more distinct circular impression, with 

 a diameter of about 5 mm., marked off by means of a circle 

 of small dots. 



The small fragment in pi. 3, fig. 8, may be described in 

 this connection. It is probably also a diaphragm but is dif- 

 ferent from the one now described. It is much smaller, only 

 about 2 mm., and has some radiating lines reaching from 

 the margin almost to the centre. This specimen may have 

 belonged to a branch, but its exact position or structure 

 cannot be determined. Similar objects have been described in 

 other species as diaphragms, so for instance in E. lateralis 

 Phill {E. columnaris Brgn.) by several authors and further 

 in E. hroraensis Stopes ^ and E. gracilis Nath, (Halle, 1. c, 

 pi. 3, fig. 15). In the latter specimen the relation to the 

 leaf-sheath is so close that its nature of a diaphragm can 

 hardly be doubted. 



It is important to note that, whereas E. Mohergii may 

 be kept as a separate species, it is more closely related to 

 younger forms, particularly E. Lyelli, than to the Rhaetic 

 E. Münster i . 



^ Stopes, M. C, The Flora of the Inferior Oolite of Brora. Quart. 

 Journ. Geol. Soc. London. Vol. 63. 1907. PI. 27, fig. 2. 



i 



