FILICES. 259 



15. IHckso nia. Fruit-dots round, very small, each on a recurved 



toothlet on the upper margin of the lobes of the pinnules, usually 

 one to each lobe. Sporangia on an elevated globular receptacle, 

 and enclosed in a cup-shaped indusium open at the top and partly 

 adherent to the reflexed toothlet of the frond. Fronds minutely 

 globular or hairy, 2-3 feet high, ovate-lanceolate in outline, pale 

 green, very thin, without chaff. 



SUBORDER II. OSMUNDA'CE^l. 



Sporangia naked, globular, pedicelled, reticulated, open- 

 ing by a vertical slit. 



16. Osniiin <la. Fertile fronds or fertile portions of the frond much 



contracted, bearing naked sporangia, which are globular, short- 

 pedicelled,arid opening by a vertical slit to discharge the spores. 

 Frond tall and upright, once- or twice-pinnate, from thick root- 

 stocks. 



SUBORDER III. OPHIOGLOSSA'CE^E. 



Sporangia naked, not reticulated, opening by a horizontal 

 slit. Fronds not circinate in the bud. 



17. Botryclt iiim. Sporangia in compound spikes, distinct, opening 



by a horizontal slit. Sterile part of the frond compound. Veins 

 free. (See Figs. 270 and 271). 



18. Opltioglos'sum. Sporangia coherent in 2 ranks on the edges of a 



simple spike. Sterile part of the frond simple. Veins reticu- 

 lated. 



1. POL^PO'DIUM, L. POLYPODY. 



P. VUlga'Pe, L. Fronds evergreen, 4-10 inches long, 

 deeply piiinatifid, the lobes obtuse and obscurely toothed. 

 Sori large. Common on shady rocks. 



2. ADIAN'TUM, L. MAIDENHAIR. 



A. peda'tum, L. Stipe upright, black and shining. The 

 frond forked at the top of the stipe, the two branches of the 

 fork recurved, and each bearing on its inner side several 

 slender spreading divisions, the latter with numerous thin 

 pinnatifid pinnules which look like the halves of pinnules, 

 owing to the midrib being close to the lower edge. Upper 

 margin of the pinnules cleft. Common in rich woods. 



