emu. GEKEEA OP PEEKS: 



Spore-cases few, loosely disposed, globose, famished witli a very 

 broad incomplete ring, of -whieli from one-third to three-fourths 

 or more is wanting, (sometimes almost obsolete consisting only 

 of 3 — i strise). Indusiwm universal, formed of the membra- 

 naceous revolute margins of the narrow siliquiform segments. 

 Veins of the sterile fronds xmiformly reticulated in oblique 

 oblong hexagonal areoles ; of the fertile few, longitudinal, dis- 

 tantly anastomosing. 



IVonds herbaceo-membranaceous, anTinnlj proliferous, bi-tri- 

 quadri-pinnatifid, dimorphous ; segments of the fertile ones 

 linear, revolute, siliquiform. Ehizome short, erect. Aquatic 

 herbs.— PorAerJffl differs only in the exaggerated reduction of 

 the strisB of the ring. The reputed species appear to be doubt- 

 fully distinct. 



Ex. : C. tlialictroides, Brongn. I C. Parkeri, J. 8m^ 



C, Gaudicliaudji, Brongn. \ C.Xockh^ti, Xze. 



Order— VOJ.Y^ODXk.CE.M. 2VJJe— OSMtraDINE^. 

 (a) I^ructifications paaiculate. 

 166. OSMTJNDA, Lmrueus, Gen. Flamt. 11B. 



ApHn-LOCALPA, Cavanilles i Stbtithiopteeis, -BerTiAardi; PLElfASluiT, 

 Bresl; OsMUlTDASTETrM, Preai; Biedlea, Jftr^eZ, in part. 



Pnictifications paniculate, terminal or lateral on contracted 

 rachiform portions of fronds, or occupying distinct contracted 

 fronds. Spore-cases crowded on the margins or over the surface 

 of the segments, obovate-globose, pedicellate or sessile, having 

 an incomplete or rudimentary gibbous ring, (represented by a 

 few parallel striss) near the apex, and bursting vertically in two 

 equal hemispherical valves. Veins forked, from a central oosta ; 

 venules itee. 



Fronds coriaceous or herbaceous, pinnate or bi-pinnate ; the 

 pionsB or segments often articulate ; fertile segments contracted, 

 usually rachiform, simple or compound, terminal medial or basal 

 on the fronds, or sometimes occupying distinct contracted fronds. 



