17 



retentive of moisture to prevent the roots from becoming withered 

 during dry weather. I have grown it for many years on the same 

 bank with Polypodium calcareum, vulgare, and other rock and epi- 

 phytic species, planting it at first in a hollow less than a foot below 

 them, and covering the rhizoma with pieces of peat turf and frag- 

 ments of stone and brick. The fertile fronds under these circum- 

 stances attained a height of nearly three feet, although under the 

 influence of the direct rays of the summer sun from eleven o'clock 

 until two. This circumstance is referred to, because it is a common 

 notion that in the cultivation of bog or marsh plants abundant 

 moisture is most essential to their luxuriance, and the unli- 

 mited supply furnished in consequence too frequently occasions 

 their destruction. The Marsh Fern will endure a more continued 

 maceration of its roots than most others, but in lieu of forming an 

 undrainable bed for its reception, as often recommended, it would 

 be following nature more closely were we to permit all unabsorbed 

 water to filter through the subsoil. My own specimens (originally 

 brought in their native turf from Epping Forest) are grown in the 

 black peat of Wimbledon Common, laid about four inches in depth 

 on the common garden loam, and covered as mentioned above, for 

 the purpose of preventing the evaporation that would take place if 

 the soil were left bare. Their share of the general watering is all 

 that the plants receive, and they have flourished for six years under 

 this treatment. 



LASTREA OREOPTERIS. Heath Fern. Mountain Fern. TAB. VIII. 



Fronds tufted, lanceolate pinnate : pinnae linear-lanceolate, pin- 

 natifid, sprinkled with resinous glands beneath; lobes oblong, 

 obtuse, flat. Sori marginal. 



Lastrea Oreopteris, PresL Aspidium Oreopteris, Swartz. Smith. 

 Hooker. E. B. Polypodium montanum, Vogler. Lastrea 

 montana, Newman, Hist. Brit. Ferns, 129. Polypodium fra- 

 grans, Linnaus. 



A native of mountainous and upland heaths and of woods, more 

 abundant in the north of England, and in Wales and Scotland, 

 than in our southern counties, where, however, it is still of frequent 

 occurrence. In Ireland it is considered rare. The fronds make 

 their appearance about the beginning of May, springing in a circle 

 from the apex of the short rhizoma, and attaining a medium height 

 of two or three feet, but varying in different situations and expo- 

 sures from one to four or even five feet. The general outline is 

 lanceolate ; but the pinna? are gradually shorter from the middle 

 downwards, until, near the base of the rachis, they often wholly 

 lose their pinnatifid character, and assume that of small triangular 



c 



