ARKIV FÖR BOTANIK. 



BAND 17. N:o i. 



i^ew YORK 



BOTANICAL, 



r. r u r>B^ 



On the sporangia of some Mesozoie ferns. 



By 



T. G. HALLE. 



With 2 plates and 1 text-figure. 



Communicated June 2nd 1920 bv A. G. Nathorst and C. Lindman. 



During the course of other palaeobotanical work I have 

 made some observations on a few specimens of fertile Meso- 

 zoie ferns among the collections of the Palaeobotanical Depart- 

 ment of the State Museum of Natural History at Stockholm. 

 Recent publications on some Mesozoie forms generally sup- 

 posed to belong to the Dipteridinae suggested an extension 

 of these studies to species of the genera Dictyophyllum, Haus- 

 mannia, and Thaumatopteris. Especially through the work 

 of Bower, the amount of the output of spores per sporangium 

 has assumed a greater significance than before, and it would 

 seem to be of some interest to consider this feature in fossil 

 ferns. In favourable cases, the number of spores may be 

 counted almost as easily and exactly in fossil material as in 

 living ferns, and, especially in the Dictyophyllum- Hausmannia 

 group, the spore-output seems to offer a character of some 

 cimportance for the discussion of the systematical position of 

 1 he fossil genera. 



Danaeopsis Hr. 



£^ The generic name Danaeopsis was instituted by Heer 

 '^1864, p. 54; pi. 2, fig. 5. — 1876—77, p. 71; pi. 24, fig. 1) 

 for a fertile Rhaetic fern believed to be identical with the 

 sterile fronds first described by Jaeger (1827, p. 28; pi. 5, 

 fig. 5) as Marantoidea arenacea and afterwards named by 

 pRESL (1838, p. 139) Taeniopteris marantacea. Kras.ser 



Arkiv für bo/unik. Band 17. N:o 1. I 



