26 Commercial Gardening 



tissue is more obscure, but some of the contents are of the nature of stored 

 food. Some cells are set apart entirely for the purpose of marrying and 

 reproducing the plant. The other cells have their respective duties, and 

 have neither time nor opportunity for this. [j. F.] 



3. PLANTS OF DISTINCTIVE CHARACTER 



Plants with Chlorophyll. Most plants with which the gardener has 

 to deal contain chlorophyll or leaf green in their leaves and the super- 

 ficial tissues of their stems, at least during the first year. It consists of 

 a green pigment colouring the large granules that develop it and lie 

 embedded in the protoplasm, but are capable of shifting their position if 

 the light is too strong for them. These green granules, under the influence 

 of sunlight and electric light, are the agents by which all raw food materials 

 are chemically changed in character and converted into organized material 

 suitable for building up the plant body and enabling it to store food for 

 future use, or to provide for its offspring. The light must be accompanied 

 by the other necessaries of plant life, such as heat, air, and moisture. 

 Green plants are thus able to manufacture their own food and lead an 

 independent existence. Crotons, Dracaenas, Coleus, and other plants with 

 highly coloured leaves have chlorophyll in their tissues, but this is obscured 

 by the presence of other colouring matters, diffused through the cell sap. 



Plants without Chlorophyll. Amongst flowering plants many species, 

 including the Broomrape (Orobanche) that lives attached to the roots of 

 Clover, and the Dodders (Cuscuta) that live on Clover, Nettles, Hop, and 

 other wild plants, have no chlorophyll in their tissues, and cannot manu- 

 facture their own food. They must needs attach themselves to the roots 

 or stems of certain green plants and absorb their food in an organized 

 form, thus robbing and injuring their hosts to a greater or less extent. 

 The Broomrape sometimes attaches itself to the roots of Pelargoniums in 

 pots, and one of them, kept under observation by the writer, was allowed 

 to flower, The result was that the Pelargonium was stunted in growth 

 and failed to recover itself, even after the parasite was removed. Such 

 plants are termed parasites, because they absorb their food from living 

 plants. The great group of fungi have no chlorophyll in their tissues, 

 and many of them are parasites, like the Club-root fungus of Cabbages, 

 the Mildew and Rust of Roses and Chrysanthemums, the Rust and Brand 

 of Wheat, and many other cultivated plants. A large number of them 

 are very minute, one-celled, and capable of producing diseases in plants, 

 man, and other animals. In these two latter cases they owe their existence 

 indirectly to green plants as the first and only manufacturers of organic 

 food. On the other hand, many fungi are harmless, because they live upon 

 dead and decaying plants and animals, and are termed saprophytes. The 

 Mushroom is one of them, and lives upon fermenting manures and other 

 decaying matter. So far it is the only plant without chlorophyll, that is 



