Revieics. — Lindley^s Theory of Horticulture. 25 



Some marvellous accounts of the temperature of the earth, 

 and its influence on the growth of plants suited to such a con- 

 dition, are given in the chapter on Temperature. These ex- 

 plain a well known fact in the successful cultivation of what 

 are technically known to florists as Cape bulbs. To flower 

 these m vigor and splendor, an alternate condition of humidity 

 and of aridity is essential. We, not long since, saw some 

 roots of Gladioli, and bulbs of Amaryllis, Haemanthus, &c., 

 which pushed strong foliage after a long voyage from Cape 

 Town, and a subsequent depreciation of soil and water, sur- 

 viving more than a year without any chance to vegetate. The 

 natural alternations of moisture and dryness in such regions, re- 

 quire, in plants indigenous, peculiarly formed functions: and 

 every gardener soon becomes aware of this fact in the culture 

 of species of many such plants. Some of these floral splenders 

 are however very diflicult to be produced, notwithstanding all 

 the art of the patient florist; though doubtless they are annually 

 destined to waste their beauty and magnificence on their na- 

 tive deserts. An antholyza in our green-houses, (we believe 

 Antholyza oethiopica?) we never saw in bloom; and after long 

 unsuccessful culture it is usually rejected as worthless. An 

 extraordinary high temperature might perhaps effect this de- 

 sired result; and this, artificially applied to other difficult 

 bloomers, might reward all effort. Series of experiments, 

 such as are suggested by such observations as follow, might be 

 advantageous in promoting the end of floricultural labors. 



There a[)pears to be no series of direct observations upon the su- 

 perficial temperature of the earth, at the different periods of verjeta- 

 tion, in other countries; but some statements are to be fonnd, here 

 and there, concerning the temperature occasionally observed, from 

 which it is to be inferred, that the earth is heated, at least for short 

 periods of time, very much above the atmosphere: and it is probable 

 that this excessive elevation of temperature is necessary to the 

 healthy condition of many plants. From some interesting observa- 



tree contains parts which previously existed as the rudiments of five leaves, the points 

 of which subsequently form the five segments of tlie calyx; and I have often succeeded 

 in obtaining every gradation of monslrosily of form, from five congregUed leaves, 

 (that is, five leaves united circularly upon an imperfect fruit-stalk) to the perfect blos- 

 som of the Pear tree. The calyx of the Rose, in some varieties, presents nearly the 

 perfect leaves of the plant, and the large and long leaves of the 3Iedlar appear to ac- 

 count for the length of the segments, in the empalement of its blossom, 'i'he calyx of 

 the blossom of the Plum and l^each tree is formed precisely as in the preceding cases, 

 except that the leaves which are transmuted into the cal\x separate at the base of the 

 fruit, and become deciduous, instead of passing through and remaining a corajionent 

 part of it." {Transactions of the Horticultural Society ,\o\. ii, p. 364. May 6, 1S17.) 



VOL. VIII. — NO. 1. 4 



