LEA 



346 



LEE 



moist food to their roots, requiring a j in which they are vegetating, though 

 competent provision for its elaboration one twenty-fifth is a still more favour- 

 and reduction from superfluous water. ! able proportion ; and as hot-beds, heated 

 Those plants which are natives of sandy | by fermenting matters, rapidly have the 

 exposed soils, have, on the other hand, air within their frames contaminated to 

 either fewer or smaller stromates. a much greater extent than the propor- 



The drier the air the greater is the tions above named, thence arises the 

 amount of moisture transpired ; and injury to the plants they contain from a 

 this becomes so excessive, if it be also too long neglected ventilation. The 

 promoted by a high temperature, that leaves turn yellow from the excess of 

 plants in hot-houses, where it has oc- acid, which they are unable to digest, 

 curred, often dry up as if burned. The , and which consequently effects that 

 justly lamented Mr. Daniell has well | change of colour which also occurs in 

 illustrated this, by showing that if the ! autumn, and which will be more fully 

 temperature of a hot-house be raised considered when the decay of plants is 

 only five degrees, viz., from 15^ to 80^, detailed. 



whilst the air within it retains the same Whatever promotes an over-luxuriant 

 degree of moisture, a plant that in the ', production of leaf-buds, proportionately 

 lower temperature exhaled 57 grains of diminishes the production of flower- 

 moisture, would in the higher tempera- buds, and the reason is obvious. A 

 ture exhale 120 grains in the same luxuriant foliage is ever attendant upon 

 space of time. Plants, however, like an over-abundant supply of moist nou- 

 animals, can bear a higher tempera- rishment to the roots, the consequent 

 ture in dry air than they can in air amount of sap generated is large, re- 

 charged with vapour ; animals are scald- quiring a proportionately increased sur- 

 ed in the latter, if the temperature is face of leaf for its elaboration, and 

 very elevated, and plants die under for the transpiration of the superfluous 

 similar circumstances as if boiled. MM. moisture; and as the bud becomes a 

 Edwards and Collin found kidney beans : branch or a root accordingly as circum- 

 sustained no injury when the air was ' stances require, so does it produce, as 

 dry at a temperature of 107^, but they may be necessary for the plant's health, 

 ■ ' ■ either leaves or flowers. — Principles of 



Gardening. 



LEBECKIA. Six species. Green- 

 house evergreen shrubs. Seeds and 

 cuttings. Sandy loam and peat. 

 LEBRETONIA. Pavonia. 

 LECHENAULTIA. Two species. 

 Green-house evergreen shrubs. Young 



died in a fev/ minutes if the air was 

 moist. 



Other plants under similar circum- 

 stances would perish, probably, at a 

 much lower temperature; and the fact 

 aff'ords a warning to the gardener to 

 have the atmosphere in his stoves very 

 drv, whenever he wishes to elevate 



their temperature for the destruction of ^^^^ gandy loam and peat, 



insects, or other purposes. Leaves have , r^o-,"T>riTc. c- 

 the power of absorbing moisture as LEC\THIS S.x species, 

 well as of emitting it, which power of evergreen shrubs. Ripe cuttings 

 absorption they principally enjoy during "^^ °^ 

 the night. 



During the day leaves also absorb 

 carbonic acid gas, which they decom- 

 pose, retaining its carbon and emitting 

 the greatest part of the oxygen that 

 enters into its composition. In the 

 night this operation is in a certain mea- 

 sure reversed, a small quantity of oxygen purposes the first year, it does not run 

 bein<T absorbed from the atmosphere, to seed until the second, the perfecting 



Stove 

 San- 



LEDON GUM. Cistus ledon. 



LEDUM. Three species. Hardy 

 evergreen shrubs. Layers. Bog earth. 



LEE-CHEE. Euphoria lichi. 



LEEK. Allium porrum. The Leek 

 is a hardy biennial, for although it at- 

 tains perfection in size and for culinary 



and a yet smaller proportion of car 

 bonic acid emitted. 



Carbonic acid gas in small propor- 

 tions is essential to the existence of 

 leaves, yet it only benefits them when 

 present in quantities not exceeding one 



of which it also often survives. 



The whole plant is eaten, being em- 

 ployed in soups, &c., and is by some 

 persons boiled and eaten with meat. 



Varieties. — There are four varieties ; 

 the Musselburgh, and the large London 



twelfth of the bulk of the atmosphere [ Leek, which are by far the best; the 



