Jb SMITH ON THE GI:NERA OF FERNS. 169 



Obs. The climbing habit of this fern is so much like tiie 

 genus Lygodium, that at first sight it might be taken for a 

 species of that genus. From Blechnum it is not only distin- 

 guished by its climbing habit, but also by the venules being 

 combined by a transverse slightly intramarginal vein, and by 

 its conspicuous cylindrical tube-like indusium bearing a por- 

 tion of the sporangia along its lengthened attachment or base. 

 Specimens of this Fern were presented me by J. Miers, Esq., 

 who informs me that it climbs to the tops of lofty trees in 

 Brazil. 



65. DooDiA, It. Br. J. Sm. 



Veins forked; venules arcuately anastomosing near their 

 base, then direct and free towards the margin ; sporangia 

 produced on the transverse anastomoses, constituting a trans- 

 verse row of oblong, straight or arcuate sori ; indusium plain. 



Fronds rigid, pinnatijid or pi?inate, margin spinulous, the 

 pinncB rarely pinnatijid; fertile frond sometimes contracted; 

 sori rarely in two rows. 



Species. 1. D. aspera, JR. Br. 2. D. Kunthiana, Gaud. 

 3. D. blechnoides, J. Cunn. 4. D. media, R. Br. 5. D. 

 caudata, U. Br, 6. D. virginica, ( Woodvvardia, Sw.~) 



Illust. Hook. Gen. Fil. t. 54. A. Gaud, in Freyc. Voy. t. 14. 



Obs. Agreeing in habit with Blechnum, but distinguished 

 from that genus by the sori not being continuous ; but that 

 character is not always to be depended upon, for Blechnum 

 hastatum often exhibits' sori of the same form, and distant 

 irom the midrib as in Doodia. With Lomaria this genus is 

 connected through D. caudata, which has somewhat contract- 

 ed fronds, with the sori nearly continuous. Sometimes 

 Doodia also presents a structure analogous to the following 

 genus, by the venules forming a second or exterior anasto- 

 mose, which anastomose is usually fertile, and therefore con- 

 stituting two transverse rows of sori. 



66. WOODWARDIA, Sm. 



Veins reticulated ; venules free exteriorly ; sporangia pro- 

 duced on the transverse costal anastomoses, constituting a 

 Journ. o/Bot. Vol. IV. No. 28, September, 1841. y 



