B OR 



97 



B OT 



pricking out is when their leaves are 

 about two inches in breadth ; they must 

 be set six inclies apart each way, and 

 watered frequently until established. 

 In four or five weeks tiiey will be of 

 sufficient growth for final removal. 



Planting. — When planted, they must 

 be set in rows two feet and a half apart 

 each way, the last plantation may be 

 six inches closer. They must be wa- 

 tered and weeded, and as they are of 

 large spreading growth, the earth can 

 only be drawn about their stems during 

 their early growth. If during stormy 

 weather any of those which acquire a 

 tall growth are blown down, they must 

 be supported by stakes, when they will 

 soon firmly re-establish themselves. 



To raise seed. — For the production of 

 seed, such plants of each variety as are ' 

 of the finest growth must be selected, 

 and either left where grown or removed I 

 during open weather in November, or 

 before the close of February, the earlier 

 the better, into rows three feet apart i 

 each way, and buried down to their 

 heads. The seed ripens about the be- 

 ginning of August. I 



BORONIA. Twelve species. Green- 

 house evergreen shrubs. Cuttings. 

 Sandy peat. 



BORRERIA. Three species. Stove 

 or green-house. Cuttings. Common 

 soil. 



BOSCI.V senegalensis. Stove ever- 

 green shrub. Cuttings. Rich clayey 

 loam. 



BOSFiA yervamora. Green-house 

 evergreen shrub. Cuttings. Loam and 

 peat. 



BOSTRICHUS, a class of beetles, 

 many of which arc very injurious to the 

 crops of the garden. 



B. dispar, Apple bark beetle. The 

 female of this insect bores into the 

 wood of the apple tree, and there depo- 

 sits her eggs, generally in the month of 

 May ; and its perforations are so nume- 

 rous and extensive, as frequently, on the 

 continent, to destroy the tree. In Eng- 

 land it rarely occurs. The perforations 

 are confined to the alburnum of the 

 wood. 



B. typographus. Typographer bark 

 beetle. This attacks the pine tribe, 

 especially the silver fir. 



B. pinaslri, Pinaster, or red bark 



beetle, confines its attacks to the pines, 



leaving the firs untouched, as the B. 



larius lives exclusively on the larch, 



7 



and the B. orthogi-aphus on the spruce 

 fir. 



BOSWELLIA, Alibanum tree. Two 

 species. Stove evergreen trees. Cut- 

 tings. Loam and peat. 



BOTANY BAY TREE, Smilax gly- 

 cyphylla. 



BOTRYCHIUM, Moonwort. Six spe- 

 cies. Hardy ferns. Division, or seed. 

 Loam and peat. 



BOTTOM HEAT. Naturally the 

 temperature of the soil always bears a 

 due relative proportion to that of the 

 air. When the temperature of the air 

 decreases, that of the soil also de- 

 creases, but very slowly ; and when the 

 atmospheric heat increases, that of the 

 soil also gradually rises. Bottom heat, 

 or heat applied below the roots of 

 plants, is the artificial mode of imitating 

 this proceeding of nature in our hot- 

 houses, and other structures of that 

 kind. If the temperature 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 fall or wither. On 

 the otherhand,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 

 branches and leaves, and as a conse- 

 quence, over luxuriant shoots, and an 

 extra development ofleaves, are caused 

 instead of blossoms, and a healthy pro- 

 gress in all the parts. 



Every plant obviously will have a 

 particular bottom heat most congenial 

 to it. Plants growing in open plains, 

 as at the Cape of Good Hope, will re- 

 quire 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 niay be the same 

 in each country. That gardener will 

 succeed in exotic plant-culture best, 

 who among his other knowledge has 

 ascertained 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 difiicult 

 to ascertain the maximum and minimum 

 temperature of the air of a country ; 

 and this being obtained, the gardener 

 may adopt this as a safe rule. Let the 

 bottom heat for plants of that country 

 be always 5* higher than the average 



