E 



F 



H 



80 OUR NATIVE FERNS AND THEIR ALLIES. 



mere traces of one around the apex, opening into two halves by 

 a longitudinal slit. 



XXX. Osmunda L. Fertile pinnae or fronds much con- 

 tracted, bearing the large and abundant sporangia on the mar- 

 gins of the narrow segments. 



ARTIFICIAL SYNOPSIS OF GENERA. 



Sporangia collected in sori and borne on the back or margin of a 



leaf}' frond g 



Sporangia in spikes or panicles not on the leafy portion of the 



frond U 



( Sori covered with indusia C 



( Sori naked p 



Fertile frond closely rolled together, entirely unlike the sterile, its 

 segments berry-like or necklace-like . .XXIII. Onoclea, p. 119 

 Sori marginal, covered with a reflexed portion of the frond . D 

 Sori marginal or terminal, borne on an elongate receptacle, 



XXVI. Trichomanes, p. 122 

 Sori dorsal or marginal, provided with special indusia ... H 



Terrestrial, growing mostly in rocky places E 



Aquatic, sterile fronds floating on the water, 



XII. Ceratopteris, p. loi 

 Sporangia at the ends of the veins, borne on a reflexed portion of the 



margin of the frond VII. Adiantum, p. 89 



Sporangia borne on a continuous, marginal, vein-like receptacle con- 

 necting the apices of the veins VIII. Pteris, p. 90 



Sporangia at or near the ends of unconnected veins, borne on the 



under surface of the frond p 



Fronds conspicuously dimorphous ; stipes light-colored, 



X. Crvptogramma, p. 97 



Fronds nearly uniform ; stipes usually dark G 



f Sori on the upper part of the veins, mostly forming a continuous mar- 

 j ginal band ; indusium membranous, continuous round the segment, 

 G J XI. Pell.«a, p. 97 



Sori minute, at the ends of the veins ; indusium interrupted, or if con- 

 tinuous, the ultimate segments usually small and bead-like ; fronds 

 mostly chaffy, woolly, or farinose, . . IX. Cheilanthes, p. 91 

 Sori roundish ; indusia not more than twice as long as broad . I 



Sori linear or oblong ; indusia more than twice as long as broad Li 



Indusium superior, attached by the centre or sinus J 



Indusium convex, fixed by a broad base partly under the sorus, 



I XXII. Cystopteris, p. 118 

 1 Indusium inferior j£ 



c ■! 



D 



