148 OUR NATIVE FERNS AND THEIR ALLIES. 



(Butler}, near St. Louis, Missouri (Eggerf). The variety in 

 cedar barrens, near Nashville, Tennessee (Gattinger). 



ft Velum complete. 



16. I. Nuttallii A. Br. Trunk almost globose, slightly 

 grooved ; leaves 20 60, slender, bright-green, 3' 9' long, with 

 only three peripheral bast-bundles ; sporangia oblong or oval, 

 entirely covered by the velum ; macrospores variable, o. 25 o. 50 

 mm. thick, densely covered with minute but rounded warts, or 

 rarely al.most smooth; microspores papillose, brown, 0.025 

 0.028 mm. long. (/. opaca Nutt.) Oregon, Washington ; West- 

 ern Idaho (Geyer), Vancouver Island (Macouri). 



** Trunk trtlobed ; velum complete. 



f tf~6 _ 17. I. Suksdorfil Baker. Leaves 12 20, firm, bright- 

 green, very slender, arcuate, deeply channelled along the face, 

 2' 3' long, less than " wide; sporangia orbicular, 2" long and 

 broad ; ligula deltoid ; macrospores grayish-white, faintly granu- 

 lated. W. Klickitat County, Washington (Suksdorf, No. 836), 

 California (Brandegee). 



