56 ALPINE OR ROCK PLANTS. 



with a pipe running along some inches below the 

 level of the earth in bottom, or a small stove, which 

 I use myself, will be quite sufficient. 



The walls of this pit may be either of brick or 

 stone I prefer the latter ; cut 6 inches by 4 inches. 

 It should be about 22 inches or 2 feet at the 

 back, and a foot or 10 inches in front, and 4J or 

 5 feet wide; the length varying according to the 

 collection. 



The interior can be neatly plastered and white 

 washed, and the sashes neatly painted and glazed, 

 and opening on hinges. 



Close wooden shutters, often used for Alpine 

 plants, are inadmissable here, as the nature and 

 treatment required by the two groups are very dif- 

 ferent ; and the want of due consideration on this one 

 point, may perhaps have been the cause that so many 

 attempts made to cultivate them have proved rather 

 unsuccessful. I have some of this group under my 

 own care, treated as here recommended, and thriving 

 most luxuriantly such as the Lycopodium, Sarra- 

 cenia, &c. , both genera are very easily brought 

 to perfection, though we find at times L. denticula- 

 tum under the shade of some stone or greenhouse 

 shrub. In this case glazed sashes are necessary, to 

 give all the light possible during the whole season, as 

 the plants are never out of the frame or pit. Though 

 expected by some, that most of them may yet be 

 brought to bear exposure in this country, I do not 

 feel very sanguine on this head. At all events, until 



