ELECTRO - HORTICULTURE 



ELEUSINE 



527 



artificial light hastens assimilation, and thereby causes 

 plants to grow more rapidly. The practical questions 

 to be considered are, therefore, the expense of using the 

 light and determining whether there are injurious ele- 

 ments in the spectrum of the given light. 



The spectrum of the electric arc light is the spectrum 

 of carbon plus that of certain gases incident upon com- 

 bustion. The spectrum of the arc light is rich in rays 

 which lie beyond the luminous part, and these rays 

 are very injurious to most plants. These rays of the 

 ultra-violet part of the spectrum are eliminated by a 

 plain glass, so that when the electric light is surrounded 

 by a globe, or when the light is hung above the roof of 

 the greenhouse, the injuries are reduced to a minimum. 

 Long-continued experiments at Cornell University have 

 shown .that each kind of plant behaves in its own way 

 in the presence of electric light. It is not possible to 

 prophesy what the results may be in a given species. A 

 few plants, as tomatoes, English cucumbers, and carrots, 

 seem to be very little affected either injuriously or bene- 

 ficially. Nearly all flowers are hastened into bloom by 

 the influence of the light, and their colors are often 

 brighter than under normal conditions ; but in many 

 instances they do not last so long. The best results 

 are secured if the light is applied to the plants when 

 they have reached nearly or quite their full stature. 

 If applied very early in their growth, they tend to 

 make flowers before the plant has attained sufficient 

 size. In floriculture, therefore, the chief practical value 

 of the electric arc light seems to be its influence in 

 hastening the flowering of certain plants in dark cli- 

 mates, or when plants must be had for a definite sea- 

 son. For instance, if the light is applied to Easter lilies 

 for a month before their normal blooming time, the 

 period of bloom may be hastened from four to ten days. 



Lettuce has shown greater beneficial results from the 

 application of the electric light than any other plant 

 with which careful experiments have been made. Let- 

 tuce which receives light from the arc lamp for half of 

 each night may be expected to reach marketable size 

 from one to two weeks before the normal crop. 



As a rule, better results are secured when the light 

 runs only half the night. A common two-thousand 

 candle-power light has a marked effect on the growth of 

 many plants at a distance of sixty to even one hundred 

 feet. The incandescent light has a similar influence, 

 but not so marked. The incandescent or Welsbach gas 

 light is also capable of hastening the growth of plants. 



As now understood, the application of the electric 

 light to the growing of plants is a special matter to be 

 used when the climate is abnormally cloudy or when it 

 is desired to hasten the maturity of crops for a particu- 

 lar date. Only in the case of lettuce has it been proved 

 to be of general commercial importance; and even with 

 lettuce, it is doubtful if it will pay for its cost in cli- 

 mates which are abundantly sunny. For the literature 

 of the subject, consult the publications of the Experi- 

 ment Stations of Cornell University and of West Vir- 



L. H. B. 



ELEOCHARIS (Greek -made word, meaning delighting 

 in marshes). Cyperacece. Rush-like native plants, 

 mostly of low, wiry growth, and commonest in marshes 

 and on muddy shores. They are mostly perennial. The 

 culms are simple, terete or angular, bearing a spherical 

 or oblong head of inconspicuous fls. : Ivs. usually re- 

 duced to mere sheaths. They are interesting for the 

 borders of ponds, and are very easy to naturalize. Three 

 species have been offered by collectors: E. equisetoides, 



'orr. A shore plant, with terete hollow culms 2-3 ft. 

 high, and cylindrical heads about the thickness of the 



ilm; resembles horse-tail (Equisetum). E. acicularis, 

 Br. Hair-like, 6 in. high, making grass-like mats. E, 



)vata, R.Br. Culms nearly terete, 12 in. high: head glo- 

 bose or ovate. L H B 



ELEPHANT'S EAR is a name for Begonias. The 

 elephant-Ear Caladium is a Colocasia. 



ELEPHANT'S FOOT. Testudinaria. 



ELETTAEIA (native name). Scitamin&cece. Differs 



om Amomum in technical characters, as in the slender 



the perianth, the presence of internal lobes in 



34 



the perianth, and the filaments, not prolonged beyond the 

 anther. Perhaps only 2 species, although more have 

 been described. E. Cardamdmum, Maton, affords the 

 small Cardamons of commerce, which are the' dried 

 capsules, and which are used in medicine. The large or 

 China Cardamons are from species of Amomum. The 

 Cardamons of Nepal and Bengal are Amomum ; those of 

 S. India are Elettaria. The Elettaria is native to India, 

 but is cult, in Jamaica, and it will no doubt thrive in 

 parts of S. Fla. Plants have been offered by Reasoner 

 Bros. The Cardamon plant grows 5-10 ft. high, bearing 

 an erect, jointed, closely sheathed stem, and lanceolate 

 acuminate entire nearly sessile Ivs. often 2 ft. long: fls. 

 purple-striped. It is said to prefer shade and a moist 

 soil. In three or four years plants give full crops, 

 but they become more or less exhausted after bearing 

 three or four crops. Prop, by dividing the roots and 

 by seeds.' Under glass, handled the same as Alpinia. 



L. H. B. 



ELEUSlNE (Greek, JKleusis, the town where Ceres, 

 the goddess of harvests, was worshipped). Graminece. 

 CRAB GRASS. YARD GRASS. Coarse, tufted annuals, with 

 the stout unilateral spikes digitate at the apex of the 

 culm. Spikelets several-fid. ; arranged in two rows 

 along one side of a continuous rachis, rachilla articulate 

 above the empty glumes : fls. perfect or the upper one 

 staminate: grain loosely enclosed by the fl. -glume and 

 palet. Species 5 or 6 in tropical regions of the Old 

 World. Some are valued as 

 cereals in Africa, India, and 

 some other eastern coun- 

 tries. For E. ^EJgyptlaca, 

 see Dactyloctenium. 



Indica, Gaertn. DOG'S 

 TAIL. WIRE GRASS. Fig. 757. 

 Erect. 2-4 ft. high ; culms 

 ascending, flattened : spikes 

 5-7, about 2-4 in. long, digi- 

 tate, often with one or two 



758. Eleusine coracana. 



757. Eleusine Indica. 



tk-xj 



lower down : spikelets 3-6- 

 fld. Blooms from June to 

 October. A very common 

 grass in cultivated fields 

 and dooryards in the South, 

 often troublesome as a weed 

 on lawns. 



coracana, Gsertn. AFRI- 

 CAN MILLET. Fig. 758. Erect, 

 2-4 ft high, closely related to and much resembling E. 

 Indica. Can be distinguished from it by its stouter 

 habit, shorter, broader and larger spikes. Cult, in 

 India, China and Japan for the grain. Beer is brewed 

 from the grain in Abyssinia. In cult, in America as 

 an ornamental grass. Coracana means "of the crows." 



BarcinonSnsis, Costa. Culms tufted, 6 in. to 1 ft. 

 high: leaf -blades short, about one-sixteenth of an in. 



