94" OPHIOGLOSSACEAE [CH. xix. 



372. Campbell. Mosses and Ferns. 3rd. edn. 1918. Here the literature is very fully 

 cited. 



373. Campbell. Eusporangiate Ferns. Washington. 191 1. 



374. Campbell. Gametophyte of ^. ^<^//^?«^;«. Ann. of Bot. 1921, p. 141. 



375. Campbell. Gametophyte of i?. .t/w/Z^x Ann. of Bot. 1922, p. 441. 



376. Bower. Origin of a Land Flora. 1908, pp. 430-494. 



377. Bower. Medullation in the Ophioglossaceae. Ann. of Bot. I9ii,p. 537. 



378. Bower. VLOX'^\v.oi O.palmatmn. Ann. of Bot. 1911, p. 227. 



379. Bower. The primitive Spindle. Proc. Roy. Soc. Edin. xliii, p. i. 1922. 



