APPENDIX. 355 



Gen. 7. Schizoccena. Sori regular. Indusium of six 

 lobes surrounding the globose receptacle. 



Family III. GLEICHEXIE^I. Sporanges united in fours 

 into sori, and surrounded by an oblique annulus, like a 

 turban. 



Gen. 1. Gleichemia. Sporangia in roundish sori. Indu- 

 sium absent. Leaves forking. 



Gen. 2. Platyzoma. Sporanges in pointlike sori. In- 

 dusium spurious, formed by re volute margin of leaf, 

 leaves undivided. 



Family IV. PARKERiE^:.--Sporanges ununited into sori, 

 and divided equally by a vertical annulus. 



Gen. 1. Ceratopteris. Sporanges surrounded by a broad, 

 complete, articulated annulus, placed on longitudinal 

 veins. Spores globose, trifariously streaked. 



Gen. 2. Parkeria. Sporanges with almost obsolete 

 basilar annulus, or longitudinal veins. Spores three-sided, 

 concentrically streaked. 



Family V. OSMUNDE^I. Sporanges united in sori, and 

 covered on the back by a broad and imperfect annulus. 



Gen. 1. Osmunda. Sporangia on metamorphosed pin- 

 nules. 



Gen. 2. Todea. Sporangia on unchanged pinnules. 



Family VI. SCHIZ.EEJE. Sporanges united in sori, and 

 annulus like a skull-cap with radiating streaks. 



Gen. 1. Aneimia. Sporangia twin, sessile in two rows, 

 on lateral lobes of leaf, contracted into a panniculate irn- 

 marginate rachis, naked, splitting longitudinally outside. 

 Xo indusium. 



Gen. 2. Schizcea. Sporanges sessile in two or four rows 

 in linear membranous-margined lobes, pectinately oppo- 



