The Ferns of Washington 9 



3. Dryopteris dilatata (Hoffm.) Gray. (Figs. 45, 



51, 52.) 



Mountain Wood Fern 



Leaf-blades broadly ovate, 3-pinnate, widest at base, 

 8-22 inches long; petioles 7-18 inches long; leaflets 

 oblong, toothed to senate.— Usually at high altitudes. 

 Alaska to Labrador, south to California, Montana and 

 Virginia; Europe; Asia. 



POLYSTICHUM. 



Leaves mostly large or medium sized, tufted; leaf- 

 blades linear to lanceolate, 1-2-pinnate; petioles more 

 or less scaly at base; leaflets numerous; veins all tree. 

 Sori only on the outer half or less of the leaf, round, 

 borne on the back of the veins; indusium round, flat, 

 peltate. (Greek pohj - many, stichos = a row; because 

 the sori are in several rows in some species.) 



A. Leaver 1-pinn ite. distinctly spinulose-dentato. 



B. Petiole y.ty ihOd : loaflet> triangular to broadly lanceolate 



1. P. lonchitis. 



BB. Petiole of medium length; leaflets linear to }*»™^ e f 



C. Leaves 2 5 feet long; leaflet, at right angles to leaf-axis, not 



Leaves 2-5 feet long; 1 \» at right angles to .«, 

 . 2. P. munilum. 



CC. TSSS M ions: ta~ ^V"££nSS2 



AA. Leaves 2-pinnate, not spinulose-dentate. 



t-v a j r 4. P. Lemmoni. 



£ n S ? ? W - 5. P. .«*«««<"»». 



DD. Sori many. 



1. POLYSTICHUM LONCHITIS (L.) Roth. (FigS. 54, 60, 

 61.) „ T, 



Holly Fern. 

 Leaves scaly along petiole and leaf-axis and mid- 

 vein of leaflets; leaf-blade 1-pinnate, linear, u m 

 inches long, scarcely petioled, hairy beneath; leaflets 

 H'H inch long, triangular or broadly lancedate, 

 auricled on upper side, margin densely spinuiose- 

 toothed. Sori very close together, one row on eacn 

 side of the mid-vein.-Subaivtic regions southward to 

 California, Colorado and New Mexico; Europe; Asia. 



