2656 



PLANT 



PLANTING 



PLANT (Latin, planta). A plant is a living organism 

 consisting of one or more cells, some of which, in most 

 of the higher forms, contain a green substance chloro- 

 phyl by the aid of which they are able in the light to 

 construct carbohydrate food-matters (as sugar, starch, 

 and the like) from carbon dioxide and water. The 

 cell protoplasm assimilates or uses these carbohydrates 

 and is nourished by them, and from the elements they 

 furnish it is able to make cellulose, the substance which 

 walls it in and gives strength and solidity to the plant. 

 Animals do not (as a rule, at least) have chlorophyl, and 

 cannot construct carbohydrates from carbon dioxide 

 and water, and the same is true of some plants, as 

 explained below. 



Green plants absorb carbon dioxide from the air, 

 and in the process of carbohydrate formation they 

 give off a certain quantity of oxygen. However, in the 

 further chemical activities of their cells, oxygen is 

 absorbed and carbon dioxide is given off. In the plants 

 which are not green (as in animals, also) the first pro- 

 cess is wanting, while the second takes place. These 

 facts have given rise to the view that plants and animals 

 are quite opposite in their physiological relations to the 

 surrounding air. They should not be contrasted, how- 

 ever, in this way; it is more exact to say that green 

 plants have two important nutritive functions, namely 

 (1) carbon absorption and fixation (technically photo- 

 synthesis), and (2) assimilation of food matters. 

 Respiration the process in which oxygen is absorbed 

 and carbon dioxide is given off occurs in all plants 

 and animals. 



With this general definition of a plant before us we 

 may say that while some lower plants are minute single 

 cells, or rows of cells, and others are flat, expanded and 

 often irregular growths, in all of which there is a marked 

 simplicity of structure, in higher plants we find the 

 plant-body composed of well-defined roots, stems, 

 leaves, flowers, fruits, and seeds. The lower plants 

 referred to perform all the functions necessary for their 

 continued existence, and are not in any sense "imper- 

 fect plants," as the older botanists used to denominate 

 them. The difference between lower and higher plants 

 is that the functions of the former are performed by 

 fewer organs, while in the latter there is an approach 

 to one organ for every function. Still it is true that 

 some organs even in the highest plants have more than 

 one function: so that it may be said that plants are 

 theoretically capable of considerably higher develop- 

 ment than they have yet attained. Thus while the 

 chief function of the root may be for the absorption of 

 food-matter, it commonly has in addition a holdfast 

 function, and may become an organ of storage also. 

 So, also, while the chief function of the leaf is to sup- 

 ply green cells for carbohydrate making (photosynthe- 

 sis), it may be used as a storage organ (as in cabbage 

 leaves), or even for making the plant more conspicuous 

 (ornamental), as in many euphorbias. Even the flower 

 usually unites two functions (that of fertilization and 

 of showiness), which in more highly specialized forms 

 are separated, as in the wild snowball where the large 

 marginal flowers are for show but are sterile, while the 

 small inconspicuous central flowers are fertile. 



One more thing must be included in our general 

 conception of the plant. While it is true that plants are 

 normally, and typically, green in color, there are many 

 plants which have so changed their food habits that 

 they are no longer green. Thus parasitic plants that 

 secure carbohydrates from living organisms, having no 

 need of chlorophyl, are not green, and the same is true 

 of saprophytic plants (those that get their food from 

 dead or decaying organisms), which are also destitute of 

 a green color. This is the explanation of the fungi, 

 lichens, bacteria, and some flowering plants (e.g., 

 dodder, Indian pipe, beech drops, and the like). Such 

 plants are more or less degenerated, and are physiologi- 

 cally like animals, but they still retain enough of the 



typical plant structure so that one is rarely at a loss 

 where to place them. 5. E. BESSEY. 



PLANTAGO (the Latin name). Plantaginacese. A 

 group of 200 or more species of annual and peren- 

 nial herbs or subshrubs occurring in many parts of the 

 world. It is a weedy genus, and only two or three species 

 have any economic or commercial value worth men- 

 tioning. They are generally known as 

 plantains, although this name is also 

 applied to certain bananas (see Musa), 

 which are plants of widely different kind. 

 P. lanceolata, Linn., or ribwort, is some- 

 times used in pasture mixtures abroad, 

 because it affords more or less spring pas- 

 turage on dry and sterile soils. The seed 

 is offered by American seedsmen for feed- 

 ing birds, but not for sowing. In this 

 country, however, it is one of the worst of 

 lawn weeds, thriving in our hot dry soils 

 when grass kills out. The best remedy 

 for it is to secure a better stand of grass, 

 and this is made possible by making the 

 ground rich and so treating it that it will 

 hold moisture. P. Corondpus, Linn., the 

 buck's-horn plantain, native to Eu., Asia, 

 and N. Afr., is sometimes eaten as a pot- 

 herb (see p. 1411). It is a low perennial, 

 with linear-lanceolate often pinnatifid Ivs. 

 It is not in the American trade. P. cordata, 

 Lam., of the E. U. S., has been offered 

 by dealers in native plants as a subject 

 for colonizing in bogs and margins of 

 ponds. It is perennial, with a stout root- 

 stock, large cordate-orbicular shining lf.- 

 blades, and a slender spike rising 1-2 ft. 

 high and bearing small pinkish fls. with 

 exserted style and stamens. P. major, 

 Linn. (Fig. 2990), is a very common door- 

 yard weed. Var. variegata, Hort., a varie- 

 gated If.-form, is offered in England. P. 

 maxima, Jacq., from Siberia, said to have 

 white feathery spikes, has been intro. into 

 England. There are about 20 native or 

 naturalized species in N. Amer. Plantago 

 is the typical genus of the Plantaginacese, 

 a family that contains two other genera, 

 bitypic and monotypic, Littorella in Eu. 

 and N. N. 'Amer., and Bougueria in the 

 Andes of Peru and Chile. ] J< jj g 



PLANTAIN: Plantago and Musa. P. Lily: Hosta. 

 Rattlesnake P.: Hieracium venosum. Wild P.: 

 Heliconia Bihai. 



PLANT-BREEDING: Breeding, p. 545. 

 (1 



2990. Spike PLANTING. This Cyclopedia considers 

 o f Plantago two classes or kinds of horticultural work, 

 major -Com- the growing of plants, and the identify- 

 "(Nat.'sTze!) 1 ' m S '* plants. The latter purpose runs 

 through every generic entry, throughout 

 the alphabet. The instructions for growing are combined 

 with these generic entries, and are also extended in many 

 separate articles, under the popular names of the -plants 

 themselves, as Rose, Strawberry, Carnation, Lettuce, 

 Mushroom, and many others; and they are also dis- 

 played in class articles, as Alpine Plants, Kitchen-Gar- 

 dening, Annuals, Biennials, Perennials, Herbs, Orchids, 

 Palms, Arboriculture, and many others. 



At this point, another set of class articles is assembled, 

 with the purpose to bring together such instruction as is 

 commonly associated with what is known as "planting," 

 with the use of plants in the open and particularly in 

 relation to their uses as a part of a landscape develop- 

 ment. In connection with this symposium, the reader 

 will naturally give special attention to the assembly on 



