40 



BRITISH FERNS. 



.MU^^ 



The preceding forms, particularly fig. h in page 39, have 

 prepared the reader for the lonchitiform or simply pinnate 

 variety of this variable plant. In the Smithian Herbarium is a 

 frond, the aculeatum, /3. of the English Flora, which was found 

 on the Welsh mountains, and of which the pinnae 

 are nearly as entire as in the accompanjdng cut, 

 and of this Sir J. E. Smith says, " it is sometimes 

 taken for A. Lonchitis." The fronds represented 

 m the margin (fig. i) were found by myself 

 at Twll-du in Caernarvonshire ; they were 

 apparently the growth of 1837, although 

 ^obtained in 1838, and the rhizoma was 

 ^ actually producing young fronds, divided 

 as in lobatum ; in cultivation this plant 

 ^^ has produced the lobatum form only, 

 j The veins of course vary greatly in 

 accordance with the divisions of the 

 frond ; they are always unconnected with 

 each other at the extremity, a character 

 which separates this genus from Aspi- 

 dium. In the pinna in the annexed cut 

 the lateral veins are three-branched ; of 

 these the anterior branch bears a mass 

 of thecae near its extremity, and is not 

 continued like the others to the margin 

 of the pinna. The indusium is orbicu- 

 lar, scale-like, and attached by a stalk in 

 the centre ; it shrivels, decreases, and 

 falls off or disappears in the centre, 

 as the thecae approach maturity : the 

 masses of thecae are circular and rarely 

 confluent : they occur only on the upper 

 part of the frond. 



I have carefully compared the frond 

 from which fig. i is drawn with the two 



km 



'VI 



^cl 



