'FILTCES. 79 



XXIV. Woodsia R. Br. Indusium roundish or stellate, 

 delicate, cleft into irregular lobes. 



TRIBE X. DICKSONIE^E, Sori roundish or transversely 

 elongate, borne at the ends of the veins or on marginal cross- 

 veinlets, with an indusium attached at the base or base and 

 sides and opening toward the margin of the segment. 



XXV. Dicksonia L'Her. Sori marginal, small, the indu- 

 sium cup-shaped, somewhat two-valved, the under portion con- 

 fluent with a lobule of the frond. 



SUB-ORDER II.-HYMENOPHYLLACE^E Endl. 



Sporangia borne on an elongate, often filiform, receptacle, 

 surrounded by a complete transverse ring, opening vertically. 

 Sori terminal or marginal from the apex of a vein. Indusium 

 inferior, usually of the same texture as the frond. Fronds deli- 

 cately membranous and pellucid. 



XXVI. Trlchomanes Sm. Indusia tubular, cup-shaped, 

 or funnel-shaped, sometimes two-lipped. 



SUB-ORDER III.-SCHIZ^EACE^E Presl. 



Sporangia ovate, sessile, arranged in spikes or panicles, hav- 

 ing a complete, transverse, articulated ring at the apex, and 

 opening by a longitudinal slit. 



* Stems scandent. 



XXVII. Lygodium Swz. Sporangia borne in a double row 

 on narrow fertile segments, each on a separate veinlet and pro- 

 vided with a special indusium. 



** Stems not scandent. 



XXVIII. Aneimia Swz. Sporangia naked, attached by 

 their bases to the narrow divisions of the panicled fertile seg- 

 ments of the frond. 



XXIX. Schizaea Sm. Sporartgia naked, fixed in a double 

 row to the midrib of the narrow fertile segments. Sterile 

 fronds simple or dichotomously forked. 



SUB-ORDER IV.-OSMUNDACEyE R. Br. 



Sporangia naked, globose, mostly pedicelled, with no ring or 



