HORTICULTURAL SOCIETY 07 LONDON*. 



159 



Cacti. If received iifter the tirst of September they should not be 

 excited into growth until March. Many Mammillariie with 

 short thick succulent roots, most Echinocacti and all Melocacti, 

 are slow in making roots after their first arrival, and, therefore, 

 should be assisted with a identic bottom heat. Indeed all the 

 Cacti are much benefited by this on their first arrival, and at 

 all times when in a ij^rowing state. No plants seem to enjoy 

 bottom heat more th in Cacti : even the species from the limits 

 of perpetual snow like it, although the heat of a close house 

 or frame would 6or»n injure them, by exhausting their vital 

 energies. 



That bottom heat is highly advantageous to these plants, even 

 in the midst of summer, the author considered proved by an ex- 

 periment instituted in the garden of Mr Harris. A glass-case, in 

 which Auriculas are wintered, was placed over a bed of hot dung ; 

 on the dung was put a layer of rough stones and gravel; and 

 three or four inches deep of light compost was placed over the 

 whole. In this were planted upwards of lOO Cacti. The case 

 had moveable sashes at the sides and both ends, with a span 

 roof of glass ; and by removing the side and end lights, the 

 plants were as much exposed to currents of air, as if they had 

 been planted out in the open border. The plants selected 

 for experiment were for the most part newly imported ; for the 

 first month the case was kept close ; afterwards the side and end 

 lights were opened, and a constant draught of air was ad- 

 mitted day and night, the plants being syringed every evening in 

 hot weather. After four months' treatment the result was com- 

 pletely successrul. Some Mexican Mammillarite had rnade roots 

 ten inches long ; and contrary to their natural habits in some 

 cases, their roots crept along close to the surface of the soil. The 

 roots of most Cacti penetrate far into the soil and insinuate them- 

 selves between the crevices of stones and rocks in quest of 

 moisture, but in this instance they kept near the surface where the 

 moisture was supphed ; a curious instance of the capability of 

 plants to accommodate themselves to particular circumstances. 



Mr Beaton next proceeded to give an account of a method of 

 applying bottom heat to Cacti at all seasons. This has been 

 effected by the following simple contrivance. Let a shelf of thin 

 Welch slate run along the whole front of the Cactus house, and 

 let hot water pipes run under this shelf and keep the slate con- 

 stantly hot. An inch of rough cinders is then strewed on the 

 shelf, and a row of inverted pots (small sixties) is placed along 

 the cinders, at about five or six feet apart. About three inches 

 of light compost is placed over the cinders with a sprinkhng 

 of sand on the top to preserve a neat appearance. A dcid board 

 is fixed along the side of the bed to keep in the soil ; and when 

 the whole is planted and finished, the bottoms of the inverted 

 pots are on a level with thj surface of the bed. Water is oc- 



