28 ARKIV FÖR BOTANIK. BAND 17. N:0 1. 



Hausmannia Forchhammeri Barth, ssp. dentata Moll. 



Fig. 19. Part of the impression, showing the sori. "/i. 



Fig. 20. Sorus from which the sporangia have been removed, 

 showing hair-like structures, 'o/i. 



Figs. 21—24. Sporangia. Figs. 21—23: '«/i. Fig. 24 is .shown in 

 the same magnification as the sporangia of Diciyophyllum, 

 Maionia and Dipteris in figs. 13 — 18, or "/i. 



Thanmatopteris Schenki Xath. 

 Figs. 25 — 26. .Sporangia. '<*/i. 



Danaeopsis marantacea (Peesl. ) Heer. 



Fig. 27. Part of fertile pinna, showing the dense and irregular 



venation. Vi- 

 Figs. 28 — 30. Parts of the same specimen, showing the relation 



of sporangia and veins. Fig. 29: */i. Figs. 28 and 30: 



is/ 



II- 



Trvckt den -i mars 1921. 



Uppsala 192L Alrnqvist & Wiksells Boktryckeri-A.-B. 



