EOT 



[ 130 ] 



BOX 



P. obli'quum (twisted). $. Brown. August 



N. Amer. 1821. 

 Virgi'nicum (Virginian). 1. Brown. August 



N. Amer. 1/90. 



BOTTLE GOURD. Lagena'ria. 

 BOTTOM-HEAT. Naturally the tem- 

 perature of the soil always bears a due 

 relative proportion to that of the air. 

 When the temperature of the air de- 

 creases, that of the soil also decreases, 

 but very slowly; and, when the atmo- 

 spheric heat increases, that of the soil 

 also gradually rises. Bottom-heat, or 

 heat applied to the roots of plants, is the 

 artificial mode of imitating this proceed- 

 ing of nature in our hothouses and other 

 structures of that kind. If the tempera- 

 ture of the soil be too cold in proportion 

 to the temperature of the atmosphere, 

 the roots are not stimulated sufficiently 

 to imbibe food as fast as it is required 

 by the branches and foliage ; and, as a 

 consequence, the leaves or fruit will full 

 or wither. On the other hand, if the 

 temperature of the soil be too great in 

 proportion to that of the atmosphere, the 

 roots absorb food faster than it can be 

 elaborated by the leaves ; find, as a con- 

 sequence, over-luxuriant shoots and an 

 extra development of leaves are caused, 

 instead of blossoms and a healthy pro- 

 gress in all the parts. 



Every plant obviously will have a par- 

 ticular bottom- heat most congenial to 

 it. Plants growing in open plains will 

 require a higher bottom-heat than those 

 growing in the shade of the South Ame- 

 rican forests, though the temperature of 

 the air out of the shade may be the same 

 in each country. That gardener will suc- 

 ceed in exotic plant-culture best, who, 

 among his other knowledge, has ascer- 

 tained the relative temperature of the 

 air and soil in which any given plant 

 grows naturally. At present, such in- 

 formation from actual observation is not 

 obtainable ; but it is not so difficult to 

 ascertain the maximum and minimum 

 temperature of the air of a country ; and, 

 these being obtained, the gardener may 

 adopt this as a safe rule : Let the bot- 

 tom-heat for plants of that country be 

 always 5 higher than the average tem- 

 perature of each month; that is, if the 

 lowest temperature of the month is 40, 

 and the highest 70, the average is 55 ; 

 and, if we add 5 to that, we shall have 

 60 as the bottom-heat for that month. 

 If the average maximum temperature of 



the air only be known, let the bottom- 

 heat be less by 10 than the maximum 

 temperature of the air. 



BOTTOMING. A term usually applied 

 to the drainage of pots, although equally 

 applicable to any kind of horticultural 

 drainage. (See DRAINING.) It is also 

 applied to mowing grtfss on lawns, and 

 signifies that the mower should take ex- 

 tra pains in mowing, cutting down almost 

 to the surface of the turf, in order to fa- 

 cilitate future mowings by the production 

 of an entirely fresh herbage, free from 

 moss and the residue of former mowings. 



BOURBON PALM. Lata'nia. 



BOURGEON, or BURGEON. See BUD. 



BOUSSINGAU'LTIA. (Named after the 

 celebrated chemist, Boussinyault. Nat. 

 ord., Basellads [Basellacese]. Linn., 6- 

 Ilexandrici \-Monoijynia,.} 



Half-hardy tuberous-rooted plant. Seeds; di- 

 vision of its tuberous roots ; peat and rich loam. 

 Summer temp., 60 to 70; winter, 45 to 55. 

 B. baselloi'des (basella-like). White. July. S. 

 Amer. 1835. 



BOUVA'RDIA. (Named after Dr. Boit- 

 rrf, curator of the Botanic Garden at 

 Paris. Nat. ord., Cinchonads [Cinchona- 

 :efe]. Linn., 4^-Tetrandria \-Monogynia.} 

 Greenhouse evergreen under-shrubs, except 

 vhere otherwise specified. Seed at times, in heat. 

 Juttings of young shoots in heat, in March or 

 April. Shut up during the day, and air given at 

 light. Also by roots, cut into pieces, and In- 

 erted in sandy soil, and placed in a brisk, sweet 

 icat, in spring. Light, fibry soil. Summer temp., 

 50 to 70 ; winter, 35 to 45. 

 B. angustifu'lia (narrow-leaved). 2. Red. Sep- 

 tember. Mexico. 1838. 

 Cavanille'sii (Cavanilles's). l. Scarlet. May. 



Mexico. 1846. 



fla'va (yellow). 



Yellow. September. Mex- 



longiflo'ra (long-flowered). 2. White. Mexico. 



1827. 



sple'ndens (shining). Scarlet. September. 



Mexico. 1834. 



strigillo'sa (small-bristled). 3. Yellow. March. 



1845. 



triphy'lla (three-leaved). 2. Scarlet. July. 



2. Scarlet. July. 

 2. Scarlet. July. 

 2. Scarlet. April. 



Mexico. 17< 

 gla'bra (smooth). 



Mexico. 1794. 

 pube'scens (downy). 



Mexico. 1794. 

 ~ sple'ndens (shining). 



Mexico. 1838. 



versi'color (various-coloured). 2. Red. Au- 

 gust. S.Amer. 1814. 



BOWER. See ARBOUR. 



Box (Bu'xus scmpervi'rcns\ is noticed 

 by the gardener chiefly as a plant suitable 

 for edgings. For this purpose it is neat ; 

 but it is an exhauster of the soil more 

 than any other that can be so employed, 



