380 CllYPTOGAMIA — FILICES. [Pteris. 



an elastic ring. Seeds minute. — Perennial plants, having- leafy 

 fronds with circinnate aestivation; in perfection during the greater 

 part of the year, especially the summer months. 



* Capsules dorsal or marginal, annulate, openincj transversely and 

 irregularly. ( Polypodiace^e, Kaitlf.) 



1. Grammitis. Sori oblong or linear, straight, scattered. 

 Involucre none. — Name ; y^aiMiJ^ri, a line ; from the lines of fruc- 

 tifications. 



2. PoLYPoDiuM. Sori roundish. Involucre 0. — Named from 

 To>.j, many, and 'xo-jz, --rodog, afoot; from the numerous roots, or 

 segments of the Jrojids. 



3. WooDsiA. Sori scattered, roundish, having, beneath, an 

 involucre which is cut at the edge into many, often capillary, 

 segments. — Named in compliment to Joseph Woods, Esq., author 

 of an excellent Monograph of the British Roses, &c. 



4. AsPiDiU3i. Sori roundish, scattered. Involucre orbicular, 

 or nearly so Name, — ae-Tig, aff-nbog, a shield, which its involu- 

 cres resemble, especially in the species of the first division. 



3. CiSToPTERis. Sori roundish. Involucre inserted, by its 

 broad cucnllate base, at the under-side of the sorus, opening by 

 a lengthened free extremity, which points towards the apex of 

 the segment. — Name compounded of xis-r,, a little box, and 

 rrnoig, a. fern. — I have taken a different view of the structure 

 of the involucre from that of Sir J. E. Smith, and I trust a cor- 

 rect one. Its texture is thin and delicate and altogether widely 

 different from Aspidium. Species with the above character 

 exist in N. and S. America, as well as in Europe. 



6. AsPLENiUM. iSor? oblong or linear. Involucres o? the s,AmQ 

 shape, arising from the lateral veins and opening on one side 

 longitudinally towards the central nerve or midrib. — Name, — a, 

 not, and crvr/.^ji/, the spleen, the plant having been supposed useful 

 in removinar obstruction of the viscera. 



■J3 



7. ScoLOPENDRiuM. Sori linear, transverse, on lateral nerves. 

 Involucre double, occupying both sides of the sorus, opening, 

 as it were, by a longitudinal suture. — Named from the lines of 

 fructification resembling the feet of a Scolopendra. 



8. Pteris. jS'ori continuous, linear, marginal. Involucres {orm- 

 ed of the 'nflexed margin of the frond, i frequently dilated into 



1 This exists, whether the fructification be present or not, and cannot there- 

 fore be deemed a true involucre, which Mr T. Smith discovered to exist on the 

 opposite side of the sorus, so narrowas to be soon concealed by the lineof cap- 

 sules in Pteris aquilina and its allied species: hence he conceives these might 

 form a distinct genus, (see Mr Smith's letter in Hook. Fl. Scot. P. ii. p. 156, 

 note); indeed, with this view of the structure of its fructification, the genus 

 does not differ from Lindsma. 



