210 EXHIBITION OF AMEKICAN PLANTS. 



MAMMILLAE I A PULCHRA TREATED AS AN AQUATIC. 



Having ascertained that Cacti grown without fresh air succeed best 

 in a moist state, I felt desirous of knowing the result, were a plant 

 exposed to the change of temperature of a greenhouse, and always kept 

 in water. In 1845, on the Uth of June, a plant of M. pulchra, in a 

 three-inch pot, was placed in a six-inch pot (not repotted), which, 

 having the hole at the bottom stopped up, has been kept full of water ; 

 and, strange as it may appear to some, the plant is still growing luxu- 

 riantly. Among most Cacti growers, it is a general rule to keep such 

 plants quite dry during winter ; and even in summer some persons are 

 afraid to give more water than just moistens the surface of the soil. 

 This single experiment, however, seems to show that the nature of 

 Cacti is as yet but imperfectly understood. — Mr. Donald, in Joxirnul of 

 Horticultural Society. 



EXHIBITION OF AMERICAN PLANTS. 



We have been much gratified by the inspection of a superb collection 

 of these plants, which have recently been exhibited in the King's-road, 

 Chelsea, by Mr. H. "Waterer, of the Knap-hill Nursery. Under a 

 large canvass roof is formed a temporary garden in three compartments, 

 with turf-margined gravel walks and some thousands of ^Vmerican 

 plants, as fresh as if they were still growing in the pure air of Knap- 

 hill, bearing evidence of how well even the most delicate plants may 

 be transplanted if proper care is exercised in taking them up with 

 large balls to the roots. The walks wind amongst the most magnifi- 

 cent Rhododendrons one can imagine, in a manner so as to fonn them 

 into groups, here and tliere intermixed with Azaleas of many colours 

 and the broad-leaved Kalmia. Besides the enormous mass of bloom, 

 varying in the Rhododendron from purple to white, and comprising 

 tiie orange and flame-coloured tints of the Azaleas, the delicate white 

 blossoms of the Kalmia, the most prominent feature is the fine standard 

 Rhododendrons, several of which are from ten to fourteen feet high, 

 with clean stems from four to five feet in height, and large spreading 

 heads bending down with the weight of bloom. Altliough these are 

 perhaps the largest and most showy plants in the collection, there are 

 many others, however, which nearly approaches them. We will not 

 attempt to enumerate all the varieties of Rhododendron and Azaleas 

 that are to be found here. We will, however, give the names of a 

 few which appeared to us more particularly deserving of notice. Of 

 Rhododendrons, multicolum maculatum is a wliite, prettily spotted 

 with brown, of excellent habit; pictum also a white, prettily spotted 

 with brownish-green ; coelestinum is a handsome delicate pink sort ; 

 catawbiense splendens, rosy pink, tinged with blue, heads compact and 

 neat — one of the best ; album grandiflorum, delicate blush, upper 

 petals nicely spotted with green ; roseum elegans, compact Iieads of rosy 

 flowers, very pretty ; album elegans, fine blush, spotted in tlie upper 

 petals with yellow ; Everestianum, a charming kind, with large dense 

 heads of lilac blossoms, closely spotted in the upper petals with green, 



