GRATIOLA 



GREENHOUSE 



1395 



GRATIOLA (Latin, grace or favor, from its reputed 

 healing properties). Scrophularidcese. Low herbs, rarely 

 planted. 



Plants with opposite Ivs.: fls. yellow or whitish, 

 peduncled, axillary, hJ•pog}^lous, perfect; calyx 5- 

 p.arted, nearly regular; corolla gamopetalous, tubular- 

 fumiclform, more or less 2-lipped; upper hp entire or 

 2-toothed, lower 3-lobed; perfect stamens 2, the 

 anterior pair wanting or rudimentary; ovary superior, 

 2-celled; style filiform; stigma dilated 2-lobed: fr. a 

 4-valved, many-seeded cajjs. — .\bout 25 species in many 

 parts of the world, none of which is of commercial 

 importance. The following species has been advertised 

 for sale and would make a good plant for covering the 

 muddy borders of ditches and aquatic gardens. RIost 

 species are perennial. 



afirea, IMuhl. Goldenpert. Golden Hedgehyssop. 

 Annual, prostrate, viscid, puberulent or glabrate: 

 Ivs. lance-oblong, 2-12 lines long, denticulate, sessile 

 by a broad base: fls. bright yellow, showy, 6-7 lines 

 long. Wet sandy shores, Maine and Oni. to Fla., 

 mostly along the coast. B.B. 3:162. 



K. M. WiEGAND. 



GRAVESIA (after C. L. Graves, who collected in 

 Madagascar). Melastomacese. Dwarf warmhouse foU- 

 age plants, natives of Madagascar, and cultivated in a 

 few American conservatories. 



Flower parts in o's or the stamens 10, all equal; pet^ 

 als obovate, obtuse or sometimes with a short spine- 

 like process: fr. a 3-valved caps. — Three species. For 

 cult, and for distinctions from alUed genera, see Berto- 

 lonia, under which name most of the varieties are still 

 known. 



guttata, Triana (Bertolonia guttata, Hook.). Caules- 

 cent, erect: branches obtusely 4-angled: petioles 2,', 2-3 

 in. long, densely scurfy-powdery: Ivs. membranous, 

 5-ncrved, rotund at base, sUghtly scurfy above and 

 spotted, under side and calyx scurfy-powdery: cymes 

 terminal, several-fid. Intro. 1865, and first described 

 in B.M. 5524 as B. guttata, where the Ivs. are shown 

 with fairly well defined, double, longitudinal rows of 

 roundish pink dots. F.S. 16:1696 is probably a copy 

 of B.M. 5.524. (See, also, Gt. 1865, p. 385, and B.H. 

 1865, p. 225.) Var. superba, Hort., I.H. 26:359 (1879), 

 is shown, with more and larger reddish pm'ple spots, 

 which are less regularly arranged. Var. Legrelleana 

 (B. Legrelleana, Van Houtte). An alleged hybrid 

 obtained by Van Houtte and figured in F.S. 23:2407. 

 Coigneu.x refers this plate to Gravesia guttata, but no 

 fls. are shown, nor have the Ivs. any spots. The nerves 

 are outlined in white, and some of the cros.s-veins for 

 short distances. Var. Alfred Bleu is brilliantly spotted 

 and lined with bright red, the nerves boldly outlined, 

 the cross-veins interruptedly outlined. I.H. 41:13 

 (1894). Var. margaritacea, Xichols. (B. margaritacea, 

 Hort. W. Yiu]l=Salpinga margaritacea. F.S. 16:1697). 

 See DC. Mon. Phan. 7:537. N. TATixjR.f 



GRAVISIA (the name unexplained). Bromeliacex. 

 South American acaulescent herbs, differing from 

 ^Echmea in the character of the pollen-grains and 

 other technical features, and requiring similar treat- 

 ment in cult. Lvs. densely rosulate, conspicuously 

 sheathing, brown-scurfy, the margin more or less spiny : 

 scape arising from the center of the rosette, bearing 

 a panicled or bipinnate infl.: petals yellow or orange. 

 G. exsudans, Mez {JSchm'ca exsitdans. Baker. 

 Tilldiidsia exsudans, Desf. Brom'elia exsudans Lodd. 

 Hohenbergia capitata, R. & S.) Fls. congested in sessile 

 heads composing a compound panicle, the floral bracts 

 spine-pointed: lvs. whitish beneath, oblong, spiny. 

 L.B.C. 9:801.— Fls. said to exude a whitish greasy 

 substance, whence the name. Plant 2-3 ft. Appar- 

 ently very little grown. L. H. B. 



GREENHOUSE. In America the word greenhouse is 



used generically for any gla.ss building in which plants 

 are grown, with the exception of coldframes and hot- 

 beds. Originally and etymologically, however, it means 

 a house in which plants are kept alive or green: in the 

 greenhouse plants are placed for winter protection, and 

 it is not expected that they shall grow. The evolution 

 of the true greenhouse seems to have begun with the 

 idea of a human dwelhng-house. At fu-st larger win- 

 dows were inserted; and later, a glass roof was added. 

 In early times it was thought best to h.ave hving-rooms 

 above the greenhouse, that it might not freeze throvigh 

 the roof. Even as late as 1806, Bernard M. Mahon, 

 writing in Philadelphia, felt called upon to combat this 

 idea. The old or original conception of a greenhouse as 

 a place for protecting and storing plants is practically 

 extinct, at least in America (Fig. 1749). In England, 

 the word greenhouse is mostly used for a house or 

 structure in which are kept or grown those plants that 

 do not require a verj' high temperature. 



Other types of plant-houses are the conservatory 

 (which see), in which plants are kept for display; the 

 forcing-house (see Forcing), in which plants are forced 

 to grow at other times than their normal season; the 



1749. The old-time greenhouse with opaque roof and sash-made 

 sides (Abercrombie, 1786). 



stove or warmhouse; the propagating-pit. Originally 

 the warmest part of the plant-house, that part in which 

 tropical plants were grown, was heated by a stove made 

 of brick, and the house itself came to be called a stove. 

 This use of the word stove to designate the warmest 

 part or room of the range is general in England, but 

 in America we prefer the word warmhouse (and this 

 word is much used in this Cyclopedia). Originally, 

 hothouse was practically equivalent to stove, but this 

 term is httle used in this country, and when used it is 

 mostly applied generically in the sense of greenhouse. 



It will thus be seen that there is no one word that 

 is properly generic for all glass plant-houses. The word 

 glasshouse has been suggested, and it is often used in 

 this work; but there are other glass houses than those 

 used for plants. It seems best, therefore, to use the 

 word greenhouse for all glass buildings in which plants 

 are grown; and American usage favors this conclusion. 



The long, low greenhouse range, of the type we now 

 know in our commercial estabhshments, probably had a 

 different origin from the high-sided greenhouse. The 

 glasshouse range appears to have developed from the 

 practice of protecting fruits and other plants against a 

 wall. In European countries, particularly in England, 

 it is the practice to train fruits and other plants on stone 

 or brick walls, that they m.ay be protected from inclem- 

 ent weather and receive the greater sun heat that is 

 stored in the ma.sonry. It occurred to Nicholas Facio 

 Duilhier to incUne these fruit walls to the horizon so 

 that they would receive the greater part of the incident 

 rays of the sun at right angles. He wTote a book on the 

 subject of "Fruit-Walls Improved," which was pub- 

 lished in England in 1699. Facio was a mathematician, 

 and he worked out the principle of the inclined walls 

 from mathematical considerations. Such walls were 

 actually built, but according to the testimony of 

 Stephen Switzer, who WTote in 1724, these walls were 

 not more successful than those which stood iierpen- 

 dicularly. Certain of these walls on the grounds of 



