32 ARKIV FÖR BOTANIK. BAND 13. NIO 7. 



figured by Berry/ and also to some other species, but the 

 material is too incomplete for an identification. 



Stem of a cycadopliyte. 



PI. 5, figs. 11, 12. 



In pi. 5, fig. 11, is figured a specimen which in all pro- 

 bability represents an impression of a cycadophytean stem. It 

 measures only 40 mm. in length, with a breadth of about 

 8 mm. The surface of the impression shows more or less 

 distinct scars, of which the outlines are not always clearly 

 defined. These scars show a certain variation in shape. Those 

 covering the larger part of the stem are rather large, round- 

 edly rhombic to triangular, 4 — 5 mm. broad and about 3 mm. 

 high. In the upper part of each scar there are a number, 

 usually five, of small dots which evidently represent scars of 

 the leaf-traces. These are arranged in a crescent, with its 

 concave side upwards. It may be pointed out, however, 

 that it is difficult to decide which is the upper and which 

 the lower end of the specimen, since probably only part of 

 the leaf-traces are shown and their arrangement shows a great 

 variation in the Cycadophyta (cf. the text-figures given by 

 WiELAND^). These larger leaf-scars are interrupted by more 

 or less marked zones of others, which are much lower in 

 respect to their breadth. These have a breadth about corre- 

 sponding to that of the others, but a height of only 1 — 2 

 mm. The zones of low scars are fairly narrow and distant 

 more than 1 cm. from each other. They are not very dis- 

 tinct, but it is evident that there really exists an alternation 

 of two kinds of scars. It is believed, in other similar stems, 

 that the large scars are caused by the leaves, the lower ones 

 by scales. 



The specimen, and a couple of similar ones still more 

 imperfectly preserved, may be compared with the stems of 

 Wielandiella {Williamsonia) angiistifolia, described by Nat- 

 horst.^ Also under the name of Bucklandia have been de- 



^ Berry, E. W., The Lower Cretaceous of Maryland : Maryland Geol. 

 Surv. 1911. P. 362. Pis. 57 and 58. 



^ Wieland, G. R., American fossil cycads. 1906. 



" Nathorst, a. G., Beiträge zur Kenntnis einiger mesozoischen Cy- 

 cadophyten. K. Svenska Vet. Akad. Handl. Bd 36. N:o 4. P. 9. Cf. 

 especially pl. 2, fig. 17. 



