46 T. G. HALLE, LOWÉR DEVONIAN PLANTS FROM RÖRAGEN IN NORWAY. 



Plate 4. 



Arthrostigma gracile Daws. 



Fig. 1. Narrow, Psilophyton-Uke stem. 



» 2. Part of the same specimen witli leaves showing tlie veins; X 2. 



» 3. Specimen with very narrow leaves. 



» 4. Specimen with umisually thick falcate leaves and slender stem; perhaps not bclonging tu this species. 



» 5. Branching specimen with thorn-like leaves; rhizome? 



Psilophyton princeps Daws. 



Fig. 6. Part of a thick stem or hranch; possibly Arthrostigma gracile. 



Figs. 7, 8. Branches with circinate tops. 



» 9 — 12. Typical branching specimens with spines. 



Fig. 13. Part of the right hand branch of the sjiecimen in fig. 12, showing the thick central zone of tracheids; 



X3. 



» 14, a and b. Tracheids from the place marked X in the specimen in fig. 12; X 00. 



? Psilophyton Goldschmidtii n. sp. 



Fig. 15. Specimen with very indistinct spines and a thick branch. 



Hostimella sp. 



Fig. 16. Large system of slender branches. 



» 17. Very slender branches. 



Dawsonites arcuatus n. gen. et sp. 



Fig. 18. Large specimen with strongly marked axis or rachis. 



» 19. Slender specimen without sporangia. 



» 20. Counterpart of the same, with sporangia; X 2. 



» 21. Thick, dichotomonsly divided specimen with sporangia. 



Tryckt den 18 november 1916. 



Uppsala 1016. Almqvist Si Wilisells Boktryckeri-A.-B. 



