24 



confounding of it with L. Oreopteris. Fructification chiefly con- 

 fined to the upper part of the frond. Mature in August and 

 September. 



The geological relations of L. rigida, its occurrence only in lime 

 stone districts, and its absence, in those districts, where other rocks 

 come above the surface, might induce the notion of the necessity of 

 imitating as much as possible its natural conditions in cultivation ; 

 hence it has been recommended to plant it among fragments of 

 limestone or old mortar, and to water it with lime-water, precau- 

 tions altogether unnecessary. As a rock-plant, it requires good 

 drainage ; as a fern, moisture and shade during the growing season 

 are favourable to its development ; but it will flourish in the ordinary 

 garden soil, and seems almost indifferent of exposure to the sun. 

 In habit and general aspect it is not at all a distinguished member 

 of its tribe, being less ornamental than most of them, and rather 

 valuable in grouping, from the contrast it affords to more graceful 

 forms than for individual beauty. When grown in pots, a mixture 

 of peat and loam with broken stone or shards below, occupying 

 about a fourth of the depth in order to ensure the -ready percola- 

 tion of water, affords the best medium, and the pots should never 

 be placed in water. Mr. Moore recommends planting it with the 

 crown of the rhizoma a little above the surface. 



LASTREA SPINTJLOSA. Narrow prickly- toothed Fern. TAB. XII. 



Fronds erect, linear-lanceolate, bipinnate : pinnules oblong, in- 

 ciso-pinnatifid, with serrate, spinose-mucronate lobes. Indusium 

 persistent, not fringed. Scales of the rachis broad, ovate, pale. 



Lastrea spinulosa, PresL Babington, Man, Moore, Handb. As- 

 pidium spinulosum, Smith. Hooker. Lophodium spinosum, 

 Newman, Hist. Brit. Ferns, 157. 



Much confusion exists in regard to this and the following species, 

 of which it is by some regarded as a variety. Though found in 

 various parts of the kingdom sparingly distributed, it seems to be 

 chiefly confined to the southern and western counties of England, 

 growing in marshy places and wet woods and thickets. The rhizoma 

 elongates slowly, branching in old plants in every direction, so that 

 when once established in any particular locality, the clusters of 

 fronds are generally numerous. It is an early grower, the fronds 

 making their appearance in April, and rapidly attaining their full 

 development, which varies from one to two or even three feet in 

 height : they are nearly erect, bipinnate, long and narrow in the 

 general outline, the pinnae being of nearly equal length throughout, 

 except toward the acuminating apex. The leafy portion occupies 



