FILICES. 145 



true indusium, while the outer seems to be a prolongation of the 

 epidermis of the margin of the frond. 



The above description is applicable only to the genus Paesia of 

 St. Hilaire, which appears to be the oldest name for the group con- 

 taining the Brake-fern, which is almost cosmopolitan, and surely 

 better deserves to retain the name of Pteris than any of the others 

 which have been left in the genus by those who have broken it up : 

 even those authors who include the Brake-fern in the genus Pteris 

 admit that in habit of growth and indusium it differs not only from 

 the genus, but also from the group Pterideae. I have therefore 

 retained the name Pteris, thinking that it is rather the less familiar 

 species which do not agree with it that should be removed. 

 Name from 7rrepis (pteris), a Fern. 



SPECIES i.-p TERIS AQUILINA. Linn. 



Plate 1886. 



Rabenh. Crypt. Vase. Exsicc. No. 122. 



Paesia aquilina, Moore, Gard. Chron. 1858, p. 878. 



Ornithopteris aquilina, John Smith, Hist. Fil. p. 298. 



Eupteris aquilina, Newm. Phytol. 1845, 277, and 1851, App. iii. ; Hist. Brit. Ferns, 



ed. iii. p. 23. 

 Allosorus aquilinus, Presl, Tent. Pterid. p. 153. 



Rootstock buried, creeping, clothed with very short brown to- 

 mentum ; its apex growing in advance of the fronds. Fronds soli- 

 tary, distant. Stipes elongate, often as long as or longer than the 

 lamina, dark and tomentose below ground like the caudex, green or 

 straw-coloured and channelled above ground, at first with hair-like 

 scales, ultimately glabrous. Lamina coriaceous, perishing in autumn, 

 light green and generally glabrous above, more or less densely 

 pubescent beneath, bending backwards from the erect stipes, deltoid- 

 ovate or triangular-ovate, tripinnate or bipinnate ; ultimate pinnge 

 triangular-strapshaped, entire or crenate or pinnatifid. Indusium 

 double, ciliated at the margin, the inner one sometimes wanting. 



In heaths and woods, very common, and generally distributed. 



England, Scotland, Ireland. Perennial. Summer, Autumn. 



Rootstock extensively creeping, as thick as the little finger. 

 Fronds variable in size, sometimes not more than a foot high in- 

 cluding the stipes, but commonly 3 or 4 feet, and not unfrequently 

 6 or 7 ; according to Mr. Moore, they reach 10 or 12 feet or even 

 more in some cases. The smaller the frond, the more deltoid and less 



VOL. XII. u 



