FONTANESIA 



FORCING 



1253 



Fortunei, Carr. (F. phillyrxmdes var. sinensis, 

 Debeaux. F. calif arnica, Hort. ). Shrub, to 15 ft.: 

 Ivs. lanceolate or ovate-lanceolate, acuminate, shining, 

 quite entire, 2-4 in. long: fls. in axillary and terminal 

 clusters, forming a narrow, leafy panicle: fr. broad, 

 oval or ovate, ^-^in. long. May, June. China. 

 R.H. 1859, p. 43. Sometimes united with the fol- 

 lowing, to which it is superior by its more vigorous 

 growth, the darker and larger foliage, and by the 

 greater hardiness. In China it is used as a hedge 

 plant and may be recommended for trial in this 

 country. 



phillyraeoides, Lab. Shrub, to 10 ft.: Ivs. ovate- 

 lanceolate or narrow-elliptic, mostly with rough, 

 minutely denticulate margin, 1^-2^ in. long: fls. 

 and frs. like those of the preceding species. W. Asia. 

 L.B.C. 14:1308. Var. angustifolia, Rehd. (F. angusti- 

 folia, Dipp.). Lvs. narrow-lanceolate or oblong- 

 lanceolate. ALFRED REHDER. 



FORAGE PLANTS are mentioned only incidentally 

 in this work, as they belong to agriculture rather than 

 to horticulture. They are mostly grasses and legumi- 

 nous plants, and have a very large special literature, 

 much of which can be secured from the United States 

 Department of Agriculture, Washington, D. C., the 

 various experiment stations, and separate books. Some 

 of the forage plants are of interest to horticulturists as 

 green-manures and cover-crops. 



FORCING. The word forcing is variously used. 

 Properly, it should designate the growing of plants 

 outside their usual or normal season. This distin- 

 guishes forcing from the ordinary purpose of the glass- 

 house, which is to imitate the usual season in which 

 plants grow. For example, begonias are not forced: we 

 endeavor to protect them and to give them the season 

 and the conditions under which they grow in the wild. 

 Carnations when flowered in the winter are forced, 

 because we transpose their seasons. Chrysanthemums 

 blooming in October and November are not forced: 

 they are only protected. Sometimes the word forcing 

 is used in a very special sense, to denote the produc- 

 tion of flowers from bulbs or tubers in a very short 

 time under the influence of a very high temperature. 

 Thus, the lily-of-the-valley may be placed in a tempera- 

 ture of 90 or above, and the large buds be forced to 

 throw out their flowers before the plant secures a firm 

 foothold on the soil. 



A forcing-house is a building in which plants are 

 forced; but the term has come to denote a simple glass- 

 house in which plants are grown only for sale, in dis- 

 tinction from private conservatories, or more elab- 

 orate structures used for the display of plants. See 

 Greenhouse. 



The forcing industry in America is very large. At 

 first it was confined mostly to cut-flowers (which see), 

 but pot-plants, vegetables and fruits are receiving more 

 and more attention. The staple forced flowers are the 

 rose, carnation, violet, lily-of-the-valley, and various 

 bulbs. These are treated under their respective names. 

 Of vegetables, the most important forcing species is 

 lettuce. This is followed by tomato, cucumber and 



radish. Other 

 vegetables are of 

 very minor im- 

 portance as forc- 

 ing products. 

 The growing of 

 fruits under glass 

 is receiving in- 

 creasing atten- 

 tion in this coun- 

 try. Very little 

 of this fruit-rais- 

 ing is really forc- 



ing, however, since the glass inclosure is used chiefly to 

 protect the plants and to enable better care to be given : 

 the fruit does not ripen much ahead of its normal season. 

 Of this category are glasshouse grapes. Strawberries 

 are really forced, however, the whole period of vegetation 

 and bloom being greatly forwarded. Much attention 

 is now given by florists to the forcing of hardy plants; 

 and this is one of the most delightful of horticultural 



1542. Even span forcing-house, 20 feet 

 wide, heated by steam. 



1543. Uneven span forcing-house, 20 feet wide, on a side hill. 

 Heated by steam. 



operations for the amateur. Many of our native plants 

 can be forced with the greatest satisfaction, but the 

 business is usually confined to imported stock of florists' 

 plants. 



The forcing-house should be of the simplest construc- 

 tion. The plan should secure the greatest amount of 

 light, economy of space and of heating, and directness 

 and simplicity in every operation. The simple sash-bar 

 frame, without rafters (Fig. 1541), is most satisfactory 

 when properly constructed. The side walls should be 

 low and the roof comparatively flat. Often there is 

 no glass on the side walls. Under most conditions, the 

 house should run north and south, particularly if 

 even in span (Fig. 1542), but the lay of the land and the 

 location of existing features usually determine the direc- 

 tion. If the house runs east and west, or if it stands on 

 sloping land (Fig. 1543), an uneven or broken span is 

 usually advisable. The widely different opinions respec- 

 ing the merits and demerits of the different spans are 

 proof that each is good under certain circumstances. 

 It is the prevailing opinion that, in broken spans, the 

 long roof should be to the south; yet formerly some 

 glasshouses had the short span which is then very 

 steep facing the south (Fig. 1546). 



In America, all forcing-houses are heated by means 

 of small wrought-iron pipes, which fit together with 

 threads. The old-time cast-iron flues may be employed 

 for conservatories, but they are too bungling for forcing- 

 houses. They do not admit of sufficient modification in 

 layout to adapt them to the long and often crooked 

 runs of forcing-house establishments. The wrought- 

 iron pipes are heated either by steam or water. Each 

 system has its advocates, which means that each has 

 its merits. Steam is less costly to install, since less pipe 

 is required. It also admits of greater variation in the 

 layout. Crooks and obstacles are more easily over- 

 come. In a large establishment, the place may be 

 heated up sooner. Hot water gives a milder heat 

 because the pipes are less hot. Of itself, it is less liable 

 to fluctuations. Theoretically, it is less expensive in 

 fuel; but in practice, the cost of running is found to 

 depend more on the character of the particular system 

 and the operations of the fireman than on the medium 

 itself. When properly installed, steam is as uniform in 

 action as water, and it is adapted to larger areas and to 

 higher temperatures (p. 1403). 



Very good shape for a forcing-house in the propor- 

 tion of breadth to length is probably as 1 is to 4 or 5. 

 The best houses are rarelv less than 18 or 20 feet wide, 

 and rarely more than 30 to 35 feet. From 400 to 800 feet 

 is considered to be a good range of profitable length. 



