April I, 1916 355 



fern" in Oregon, and is the one most used for holiday and oilier 

 decoration in Portland, for which pnrposc its tall, ji^racefnl fronds 

 (2 to 4 feet long^) are eminently suited. It rtadily adapts itself 

 to cultivation and can be found growing^ in numerous private 

 grotuids throiighont the city. June to August. 



DryopTKRIS Adans. Shield fern. Wood fern. 

 Dryoptkrisspinui.osa dilatata (Hoffin.) Undervv. Gland- 

 ular wood fern. Stream banks and dense moist woods, Balch 

 creek, St. Helens road. June, July. 



DryopTERIS arguta (Kaulf.). Western wood fern. Dry 

 rocky ridges near Milwaiikie. June, July. 



WOODSIA R. Br. Northern fern. 

 WOODSIA SCOPUi.iNA D. C. Eatou. Western Woodsia. Com- 

 mon on shady cliffs. Rocky Butte and Willamette river. June 

 to August. 



MARSILEACEAE R. Br. Marsilea Family. 

 Marsilea L. Four-leaved clover. 

 Marsilea VESTiT A Hook. & Grev. Hairy four-leaved clo- 

 ver. Wet, sandy banks, Willamette river, Bridgeton, Hayden 

 island, etc. May to July. 



SALVINIACEAE Reich. Salvinia Family. 

 AzoLLA Lam. Water moss. 

 Azoi.LA CAROUNIANA Willd. Floating' waterweed. In 

 ponds, Oswego, Oak Grove, East Portland, etc. May to July. 



EQUISETACEAE Michx. Horsetail Family. 

 EquiSETUM L. Horsetail, Scouring rush. 

 Equisetum arvense L. Field horsetail. Moist ground. 

 Guild's lake, Swan island, etc. March to May. Sterile, May, 

 June. 



Equisetum robustum A. Br. Large scouring rush. Wet 

 places and stream bank?, Willamatte liver. April to August. 



Equisetum hyrmale L. Scouring rush. Stream banks 

 and wet places, Macleay Park, Mt. Tabor, etc. April to August. 



