100 



CASSELL'S POPULAK GARDENING. 



soil may he' altered in character, takei up and 

 utilised By the plant. The phenomena also show 

 very remarkahly the interdependence of living or- 

 ganisms of various natures one upon another, and 

 upon mineral matters, and they give some hint of 

 the changes and activity going on in that soil which 

 the generality of people still look on more especially, 

 hut very erroneously, as an illustration of fixity and 

 repose. 



Solvent Action of the Boots.— Another means 

 by which insoluble matters in the soil become 

 taken up by the plant is explained by the solvent 

 action exercised by the roots themselves. The 

 tips of the roots above the root-cap, or the extreme 

 ends of the root-haira, come into close contact with 

 the particles of soil, and then 

 an acid exudation from the 

 cell takes place, which imme- 

 diately attacks the particles 

 of soil, and aided by the water 

 around it, effects the solution 

 of the mineral matter which 

 it contains. The solution is 

 absorbed as fast as it is pro- 

 duced, and so none is per- 

 ceptible in the soil itself. It 

 is, however, to be noticed that 

 this acid exudation from the 



cell-wall is produced as a -gp^^ Eose, 



consequence of direct contact 

 with suitable matter, but not 



otherwise, just as the gastric juice in the stomach of 

 an animal is only produced when the glands which 

 secrete it are directly stimulated by the presence 

 of food. 



Summary. — So far then as we know at present, 

 liquid food, or rather liquid materials capable of 

 being converted into food, are introduced into the 

 roots of plants in one or other of three ways — by 

 direct osmotic absorption or diffusion, as in the case 

 of water and substances dissolved in it; by the agency 

 of "microbes," which turn the insoluble into the 

 soluble ; and by the agency of the roots themselves in 

 furnishing at the right moment, and in the right 

 quantity, a proper solvent. 



The substances introduced into the plant by the 

 roots are, first and foremost, water; then mineral 

 matters, of which potash and phosphates are among 

 the most important, and nitrates, which supply the 

 nitrogen that is a constant component element of 

 protoplasm, and hence illustrates the reason why 

 nitrogenous manures, such as guano, nitrate of 

 soda, or ammonia-salts, are so valuable in promoting 

 vegetation. 



COMMON GAEDBN FLOWERS. 



The Common Boek Eose. — This well-known 

 British and European plant is Eelimthemum imlgare, 

 the name being derived from the Greek helios, the 

 sun ; and mthemm, a flower. Vttlgare means com- 

 mon, and refers to the prevalence of the plant. It 

 is also known as the Sun. Eose, the Little Sunflower, 

 and the Dwarf Cistus. Linnaeus named it Ciatuie 

 helianthemum. It is to be found in plenty in dry and 

 hilly pastures, or in chalky or gravelly soil. There 

 are several species which were introduced from dif- 

 ferent parts of Europe, and one, at least, from North 

 America ; but the fine varieties which are now found 

 in cultivation are really very handsome and showy 

 plants, which are probably seedlings from S. vulgme, 

 though some are imagined to 

 be distinct species. They are 

 well termed a beautiful class 

 of perennials, and they are 

 excellent for rough rock- 

 work, where they can take 

 root between the stones ; also 

 for banks, edgings, &c., in hot 

 and exposed situations ; they 

 appear to thrive on any soil, 

 but show to the greatest ad- 

 vantage on a chalky one; 

 the fiowers are rather tran- 

 sient, but produced in such 

 quantities and so continu- 

 ously, that tufts are covered 

 with blossom for a considerable period of the year. 

 The close, compact, trailing growth particularly fits- 

 them for' planting near ledges, where they can hang 

 down over the front, as in the case of rock-work. 

 Certain varieties can be increased in the readiest 

 manner by dividing the roots in the autumn and 

 spring, or by saving seed and sowing it in the open 

 ground. 



There are a few double varieties that produce large 

 full flowers of a very showy character, viz., the rosy- 

 bufE, chocolate, sulphur, and yellow. Of single 

 varieties, the following are well deserving atten- 

 tion : — 



Cecilia, straw and yellow. 

 Garibaldi. 

 Lady Elizabeth. 

 Ma^iificeut, primrose and 

 orange, 



LyohnlB.— This genus comprehends a rather nu- 

 merous group of hardy herbaceous perennials, a few 

 of which are very handsome border plants. The name 

 Lychnis — from lychnos, a lamp — ^refers to the bril- 

 liancy of the flowers. One of the best known is 

 Zyclmia chaicedonica ; this is a well-known old border 

 plant, growing two feet or so in height, and bearing 



Oculata. 



Sudbury Gem, ricli rose. 

 Timnum florepleno. 

 Ydlow Beauty, 



