116 



GARDEN MA^•AGEiIE^'T. 



force, advocating the theorj'- of electrical action in place of it, fiudiug tliat the 

 magnet exercised no influence over the circulation ia chara, admitted afterwards 

 the doctrine of vital force. The sensitive plant, which shrinks from the touch, the 

 lip of Drakaea which closes under similar curcumstances, and the snap of the leaf 

 of Dionsea, are all arguments favouring the doctrine, \vhich is confirmed by the 

 efifect of laudanum or arsenic dropped ontheleaf of plants, such as the kidney- 

 bean or lilac, or two drops of chloroform placed on the leaf of the sensitive 

 plant, the leaflets collapsing pair by pair at the extremity, but recovering their 

 sensibility after some hours. 



252. In a state of nature all pknts are propagated from seed, and the 

 multifarious forms of the seeds and envelopes with which they are provided 

 form one of the many interesting subjects of investigation to the lover of 

 nature. For our purpose it is sufficient to state that most seeds are covered 

 with a hard shell or envelope, which protects them from external injury ; that 

 within the envelope lies the embryo plant. All seeds in this latent state 

 contain an organ, or Geem, which, under favourable circumstances, shoots 

 upwards, and becomes the stem of the plant ; another, called the Radicle, 

 •which seeks its place in the soil, and becomes the root ; and the Seed-Lobes, 

 ■which yield nourishment to the young plant in its first stage of growth. 

 Moistm-e, heat, and air, are necessary conditions for the development of all 

 seeds; and most of them require, in addition, concealment from the light. 

 These conditions are found in the open texture of well-pulverized garden soil, 

 through which water percolates freely, and au" follows, each yielding their 

 quota of oxygen, hydrogen, and carbon, in a gaseous state, for the support of 

 the plant. The great majority of plants cultivated in a garden are obtained 

 by sowing the seeds in beds suited to their constitution, to be afterwards 

 planted out where they are to grow and ripen theu- fruits, or seeds, or leaves. 

 Leaves are the first outward sign of germination, and throughout its existence, 

 next to the roots, the most important organ of a plant. The seed-leaves, as 

 the buds which first appear above the ground are termed, are of vital 

 importance to the plant, and, if destroyed prematm-ely, the young plant rarely 



recovers ; therefore the leaves of all young 

 seedlings require protection from insects, 

 worms, and slugs, their most dangerous ene- 

 mies, as well as fi-om severe weather. 



-53- Geniii7iatio)i is the art by which the 

 embrj'o of the seed placed in favourable cir- 

 cumstances, that is, surrounded by moisture 

 and heat, and placed in darkness, throws off its 

 shell or covering, and in course of time becomes 

 a vegetable, resembling that which gave it 

 birth. From the time that the acorn of the 

 oak is placed in circumstances favourable to its 

 gei-mination, it absorbs humidity, the cotyledon A swells, the root or radicle 

 B is elongated, ihe shell or envelope C is broken. The root isuses by tho 



