LASTREA DILATATA. 287 



Lastrea cristata, my attention has been specially directed to 

 these plants, and the conclusion arrived at is that they cannot 

 be grouped with each other. The other similar form is a 

 Avide-spread Fern, but always found in woods growing in 

 similar situations to those suitable to Lastrea dilatata, but 

 unlike that species, sending its roots perpendicularly down into 

 the subsoil, it is always upright in growth, and having very 

 long naked stems. I have seen it in woods at Bulwell and 

 AVollaton, in Nottinghamshire; in the lake district; near High- 

 force, in Durham; at Chaigeley Manor and Browsholme Hall, 

 Lancashire; and at Matlock, in Derbyshire, yet in no place 

 have I found it where Lastrea cristata grows. Then again, 

 Lastrea • spinulosa has often been associated with Lastrea 

 dilatata, and some growers have even affirmed that the pinnae 

 and pinnules of the former have in course of time expanded 

 into similar ones to those of the latter. Plants in my Fernery, 

 ten and fifteen years old, have never altered their character. 

 Provisionally, however, we will group all these Ferns under 

 Lastrea dilatata, yet with a firm conviction that they cannot 

 long remain united. 



After describing the varieties we may return to the subject. 



The normal form occurs at every elevation from the sea 

 level to more than three thousand six hundred feet in height. 



The fronds vary from twelve inches to six feet in length, 

 and from four to eighteen inches in breadth. Spreading, and 

 usually drooping; ovate, or ovate-lanceolate in form, and 

 bipinnate or tripinnate. Pinnce distant below, becoming more 

 approximate upwards; numerous, and opposite or subopposite. 

 The basal pair are obliquely-triangular elongate, the posterior 

 much larger than the anterior. 



Pinnules ovate-oblong, the basal ones stalked, the upper 

 ones sessile and decurrent, all the divisions are sharply dentate, 

 and terminating in a bristle-like point. 



Veins branching. 



Fructification occupying the whole underside of the frond. 



Stipes terminal, and adherent to the caudex, variable in 

 length, very thick at the base, and densely scaly. Rachis 

 convex behind, and channeled in front. 



Caudex stout, and mostly erect. 



