174 Filices. 



668 Fronds all similar, .... Pteris VII. 



668 Fertile and barren fronds unlike, 670 

 669 Sori linear, 671 



669 Sori globose, 672 



670 Barren fronds pinnatifid with entire 



segments, Blechnum VIII. 



670 Barren fronds bi- or tri-pinnate, . . . Allosorus IX. 

 671 Sori and indusium single, 673 



671 Sori double parallel, indusium double, . . Scolopendrium X. 



672 Indusium hooded, on one side of the sorus, Cystopteris XI. 



672 Indusium roundish, above the sorus, 674 

 673 Indusium with entire margins, ..... Asplenium XII. 

 673 Indusium fringed at the end, Athyrium XIII. 



674 Indusium circular, .... Polystichum XIV. 



674 Indusium reniform, Lastrea XV. 



\,—OSMUNDA. 



OSMUN'DA REGA'LIS (85). Royal Fern. 6—8. Stem 2—10 ft. 

 {1806) high, fronds bipinnate fertile at the top the thecae forming a terminal 

 brown panicle. Bogs^ locally abundant. 



ll.—HYMENOPHYLL UM. 



Hymenophyl'lum unilatera'le (47). Filmy Fern. 6—7. Stem i — 3 in. 

 (1762) filiform creeping, fronds transparent pinnate, pinnules curving back- 

 wards serrate. Fig. p. 173. \G. {Ingleborough.) 



IW.—OPHIOGLOSSUM. 



OPHIOGLOS'SUM VULGA'TUM (87). Adder's Tongue. 6—8. 

 (1807) Stem 2—8 in., fronds a barren oblong or lanceolate frond and a fertile 

 2-rowed spike of sori. Moist pastures. 



. \N.—BOTRYCHIUM. 



BOTRYCH'IUM LUNA'RIA (96). Moon- wort. 6—8. Barren frond 

 (1809) pinnate erect with semicircular closely set pinnae, fertile frond a terminal 

 panicle. Pastures and banks. 



N.—CETERACH. 



CE'TERACH OFFICINA'RUM (65). Scaly Fern. 4—10. Frond 

 (1781) leathery 4 — 6 in. pinnatifid green above densely covered with brown 



scales beneath, sori oblong covered with chaffy scales, indusium absent. 



Rocks and walls. 



