176 COMMON CANADIAN WILD PLANTS. 



SUBORDER IT. OSMUNDA'CEJE. 



Sporangia naked, globular, pedicelled, reticulated, opening by 

 a vertical slit. 



15. Osmuii'da. Fertile fronds or fertile portions of the frond much con- 



tracted, bearing naked sporangia, which are globular, short-pedicel led, 

 and opening by a vertical slit to discharge the spores. Frond tall and 

 upright, once- or twice-pinnate, from thick rootstocks. 



SUBORDER III. OPHIOGLOSSA'CE^E. 



Sporangia naked, not reticulated, opening by a horizontal slit. 

 Fronds not circinate in the bud. 



16. Botrycli'ium. Sporangia in compound spikes, distinct, opening by a 



horizontal slit. Sterile part of the frond compound. Veins free. (See 

 Figs. 270 and 271.) 



17. Opiiioglos'suin. Sporangia coherent in 2 ranks on thj edges of a simple 



spike. Sterile part of the frond simple. Veins reticulated. 



1. POIiYPO'DIUM, L. POLYPODY. 



P. Vlllga're, L. Fronds evergreen, 4-10 inches long, deeply 

 pinnatitid, the lobes obtuse and obscurely toothed. Sori large. 

 Common on shady rocks. 



a. 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 pin- 

 nules cleft. Common in rich woods. 



3. PTE'RIS, L. BRAKE. BRACKEN. 



P. aquili'na, L. Stipe stout and erect. Frond large and 

 divided into 3 large spreading divisions at the summit of the 

 stipe, the branches twice-pinnate, the pinnules margined all 

 round with the indusium. Common in thickets and on dry hill- 

 sides. 



4. PELLJE'A, Link. CI.IFF-JJKAKK. 



1. P. gra'cilis, Hook. Fronds 3-6 inches high, slender, of few 

 pinna?, the lower ones oiice- or twice-pinuatilid into 3-5 divisions, 



