POLYPODIACEAE. 



segments which are small and bead- 

 like (in ours). 

 Fruit dots on the lower surface or margin of the 

 leaf, each with a special indusium. 

 Fruit dots linear or oblong; indusium more 

 than twice as long as broad. 

 Fruit dots all parallel with the midribs. 

 Veins free. 



Veins forming a network. 

 Fruit dots all oblique to the midribs. 



Fruit dots straight, on the upper side 



of the veins. 

 Fruit dots curved, often crossing the 

 vein. 

 Fruit dots roundish ; indusium less than twice 

 as long as broad. 

 Indusium conspicuous, centrally attached. 

 Indusium rotund and attached at its 



center. 

 Indusium heart-shaped and attached 

 at the middle of the sinus. 

 Indusium inconspicuous, not attached at 

 the center. 

 Indusium hood-like or arched, attached 

 by a broad base on the inner side 

 partly under the fruit-dot, early 

 withering. 

 Indusium rotund or star-shaped, at- 

 tached under the fruit-dot. 



7. Cheilanthes, S. 



8. Struthiopteris, 5. 



9. woodwardia, s. 



10. asplenium, 6. 



11. Athyrium, 6. 



12. polystichum, 6. 



13. Dryopteris, 7. 



14. Filix, 8. 



15. Woodsia, 8. 



1. CEROPTERIS. 



Fruit-dots oblong or linear, following the course of the vein- 

 lets, and like them simple, forked, pinnate or variously anasto- 

 mosing, obscured by a yellowish or white powder on the back of 

 the leaf (in ours) ; indusia wanting. 



Ceropteris triangularis (Kaulf.) Underw. {Gymnogramme triangularis 

 Kaulf.) Gold-back Fern. Stalks tufted, slender, dark brown, shiny, 15-30 cm. 

 long; blades triangular or pentagonal, 5-12 cm. broad and long, pinnate; 

 lower divisions largest, bipinnatifid, the others pinnately lobed; under surface 

 of the leaf covered with a yellow powder. 



Crevices of rocks, mostly near the sea coast. Vancouver Island to Cali- 

 fornia and Arizona. Nanaimo, Mount Finlayson, Victoria, San Juan Island, 

 Port Angeles, Eatonville. More common on the Oregon coast. 



2. POLYPODIUM. 



Fruit dots round, without indusia, on the back of the leaf, 

 in one or more rows on each side of the midrib, or irregularly 

 scattered; petioles jointed to the root-stock. 



P. scouleri. 



P. occidentale. 

 P. hesperium. 



Leaves leathery; veins more or less netted. 

 Leaves membranous; veins free. 



Leaflets attenuate, acute or acuminate. 



Leaflets short, obtuse. 



