Culture of Orchideous Plants. 285 



c had elongated two inches and a half, and was scarcely 



altered in colour at the base. 

 d had elongated three inches and three fourths of an inch, 

 and remained natural, or unaltered in respect of 

 colour at the base. 

 The inference which I draw from this experiment is, that 

 the sap must be raised to the apex of the leaf, in order 

 to undergo that change which ,.is necessary to render it, on 

 descending, fit to be assimilated into the substance of the bulb ; 

 and that it is from this altered sap, that the increase to the 

 leaves is derived : or, in other words, that the apex of the leaf 

 in bulbiferous plants performs the same function as the entire 

 leaf in trees and shrubs. 



I remain, Dear Sir, yours faithfully, 



Anthony Todd Thomson. 

 3. Hinde Street, Manchester Square, 

 March, 12. 1827- 



Art. XIII. On the Culture of Orchideous Plants. By A. X. 



Sir, 



The native orchidese will thrive tolerably well under the 

 following treatment: Choose a spot on a north border, or 

 north side of a hedge, which is sheltered from the sun in the 

 middle of the day, and as much protected from cutting frost 

 winds in spring as possible. Take out the soil to the depth 

 of twelve inches ; lay three inches of brick-bats at the bottom 

 of the excavation ; cover them with thin turf, and fill up the 

 remaining space with a compost of one half melon loam, one 

 fourth of peat, and one fourth of sand. Plant the roots about 

 three inches deep, surrounding the bulb with an inch of sand, 

 which will prevent them from perishing in wet weather, by ab- 

 sorbing the moisture during the time they are in a dormant 

 state. Put a light covering of furze or fern over the bed in 

 March and April to shelter them from cutting frost winds. At 

 this season they frequently get cut off even in their native 

 places of growth by the severity of the weather. The species 

 that will succeed treated in this way are, Habenaria bifolia ; 

 O'rchis Morio, mascula, latifolia, maculata ; Gymnadenia con- 

 opsea; Herminium Monorchis ; Listera ovata; Epipactis 

 latif61ia, and palustris. 



The following species are more tender, and, to ensure their 

 preservation for years, they ought to be potted in the same 

 compost as directed for the bed above described, with plenty 



