matter appears to be occasionally absorbed by the root.  This colouring substance is, however, never a deep green.  Red and yellow, as may be seen in forced rhubarb, &c., are the most common hues.  Succulent plants are less susceptible of the influence of light than any others.  As they are always natives of hot countries, nature, to prevent the danger they would be exposed to from excessive evaporation, has provided them with leaves almost destitute of pores; and the moisture they absorb by their roots thus remains for the nourishment of the plant.  It is for this reason that cactuses, mesembryanthemums, and other plants of a similar description, require very little water when kept in pots.  Scarcely any carbon is found in plants grown in the dark.  Many experiments have been tried to show the stimulus afforded to vegetation by light; trees of the same species and variety have been planted in the same garden and the same soil, but against walls with different aspects, and differently situated with regard to shade.  The effect has been, not only a difference in the growth and appearance of the tree, but also in the size, colour, and flavour of the fruit which it produced.  The contrast between plants grown in hot-houses with wooden sash frames, and those grown in hot-houses with iron sash-frames, has been found equally striking; the difference of light between the two kinds of houses being as seven to twenty-seven, or, sometimes, as three to twenty-three.  Light is required at an early period of vegetation; but, as its properties are to give strength and flavour, it must be admitted with caution, as it is sometimes injurious.  Too much light renders the skin of fruits tough, and will make cucumbers bitter.  Berard of Montpelier found that the ripening of fruits is merely the turning the acid which they contain into sugar, by exposure to the light; and that too much light and heat, before they have attained their proper size, will bring on premature ripening, and make them insipid.

Lindley’s Lectures, reported in the Gardeners’ Magazine.

* * * * *

PLANTS IN ROOMS.

It is very difficult to make plants grow in rooms.  They must necessarily be deficient in the three important auxiliaries to vegetable life, light, air, and moisture; the latter of which cannot be maintained in apartments that are daily occupied.  In large towns, plants cannot thrive even in the open air, as the minute particles of soot, which are constantly floating about, settle upon their leaves, and choke up their pores.  The gases produced by the combustion of coal, &c., are also injurious to plants.  Sulphurous acid, which abounds in the atmosphere of London, turns the leaves yellow; and the want of evaporation and absorption by the leaves prevents the proper elaboration of the sap, and makes the trees stunted and unproductive.

Ibid.