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EosE OF J ERicno.—Anastdtica 

 Jnerochunthia. — A cruciferous an- 

 nual from the Levant, of no beauty, 

 Lut curious, from the manner in 

 which its branches curl round the 

 seeds when they are ripe. The end 

 of the shoot containing the seeds 

 thus protected falls oif, and is blown 

 by the wind from place to place 

 without discharging the seeds, so 

 long as it is dry ; but as soon as the 

 ball reaches a moist place, where 

 the seeds can germinate, the pro- 

 tecting branches relax, and the seeds 

 drop out. There is a species of 

 Lycopodium from tropical America, 

 L. lepidophijllum, which curls up 

 like the Rose of Jericho, and is 

 often mistaken for it. 



KosE-KOOT. — See Rhodi'ola. 



Rotation of Crops. • — It has 

 heen found by a series of experi- 

 ments, that the same kind of annual 

 plant should never be grown for 

 more than two years in succession 

 in the same ground, without ma- 

 nuring or renewing the soil ; as 

 plants exhaust the soil of those 

 salts which are nourishing for them. 

 The groimd, however, which thus 

 becomes unfit for one kind of plant, 

 is found to be suitable for another 

 kind quite different ; and the making 

 these plants succeed each other in a 

 proper manner is called the rota- 

 tion of crops. Perennial plants, and 

 trees and shrubs, are not so liable 

 to injury from their exhausting the 

 soil, as they elongate their roots 

 every year, so as to have their 

 spongioles always in fresh soil ; but 

 some shrubs, such as Roses, which 

 never have long roots, should either 

 be transplanted every third or fourth 

 year, or have manure laid on the 

 surface of the soil, to supply them 

 ■with fresh food. 



Rot-heap. — A heap composed of 

 sand, and such fruit as haws, holly- 

 berries, ash-keys, hornbeam-nuts, 



and similar seed-vessels, which is 

 turned over several times in the 

 course of the winter, to promote 

 the decomposition of the exterior 

 covering of the seed. The object is 

 to save i^om in the nursery, because 

 these seeds, and others, if sown 

 before the flesh or exterior covering 

 is rotted off, will lie dormant in the 

 soil for a year ; whereas by rotting 

 it off and sowing the seeds in the 

 spring of the second year after 

 which they are gathered, they come 

 up the following May or June. The 

 rot-heap is kept in what is called 

 the rotting-ground, which may be 

 in any open situation fully exposed 

 to the weather. The heaps may be 

 one or two feet in thickness, and of 

 any convenient width, the object 

 being to produce decay without in- 

 ducing such an active fermentation 

 as would generate sufficient heat to 

 destroy the vital principle in the 

 seeds. 



Rough Potting. — This is a 

 most important improvement in the 

 system of growing plants in pots ; 

 and it consists in filling the pot 

 with rough pieces of turf, pieces of 

 charcoal, and stones, so as to allow 

 air to pass freely to the roots. It 

 is well known that plants will 

 neither produce flowers nor fruit 

 without an ample supply of car- 

 bonic acid gas, which they obtain 

 from the air. 



Rubbish — such as broken bricks, 

 stones, remains of old walls, &c. — 

 is of great use for laying at the bot- 

 tom of a flower-bed or border in an 

 open garden in which bulbs are to 

 be grown. A similar bed has also 

 been found very useful for growing 

 Dahlias, as they are very liable to 

 be injured by stagnant moisture. 



Rumbus. — Rosdcece. — The Bram- 

 ble. — There are but few ornamental 

 species of this very extensive genus. 

 R. odoratus, the flowering Rasp- 



