FILICES. 51 



Shetland. In Ireland it is rather local and rare, but widely distri- 

 buted from south to north. 



England, Scotland, Ireland. Perennial. Summer. 



Caudex very similar to that of P. Dryopteris, but thicker, and 

 finely pubescent. This pubescence is more persistent than that on 

 the caudex of P. Robertianum, and does not come off in flocculi, as in 

 that plant ; the hairs, too, are considerably shorter. The scales on the 

 caudex are considerably narrower, more acute, and darker coloured 

 than in P. Dryopteris. The .fronds are £ to 1 inch apart. The stipes 

 is 3 to 12 inches long, thicker than that of P. Dryopteris, and like it 

 very brittle, but is not so thick as that of P. Robertianum ; at first 

 it is pitchy at the base, and usually with a good many scales similar 

 to those on the caudex, while those above are narrower ; it is also 

 sparingly clothed with very minute whitish spreading or reflexed 

 hairs. The lamina is 3 to 8 inches long by 2 to 5^ inches broad; the 

 rachis and midrib of the pinnae are clothed with minute narrowly 

 subulate whitish scales, as well as minute hairs. The texture of the 

 frond is much firmer than in P. Dryopteris, but less so than in 

 P. Robertianum, and it is also intermediate in colour between the 

 two. The pinnae are more or less deeply pinnatifid or pinnatipartite, 

 at least towards the base. The first pair of pinnae, which are as long 

 as, or nearly as long as, the second pair, are directed slightly down- 

 wards, so as to form acute angles with the succeeding pair, and are 

 not parallel to them. The uppermost pinnae are combined, so that 

 the apical half of the frond is pinnatipartite, not pinnate. The sori 

 are usually less numerous than in P. Robertianum and P. calcareum, 

 and are often more or less oval. 



Beech Fern, or Mountain Polypody. 



GENUS VIII.— LASTREA. Presl. 



Fronds produced from the extremity of the caudex, approximate 

 and tufted or solitary, membranous or subcoriaceous, once or more 

 times pinnate ; stipes not articulated to the caudex. Veins all free. 

 Sori punctiform, round, at the extremity of the ultimate veins, or 

 attached to some portion of their back. Indusium round or reniform, 

 with a sinus at the base, by which it is attached ; rarely the indusium 

 is absent or fugacious. 



Name after the Chevalier de Lastre, a French botanist and microscopist. 



H 2 



