322 



CITRON 



CITRUS 



during the summer all cultivation is stopped, and grass, 

 beggar-weed, or field-peas allowed to cover the ground, 

 preventing sunburning and providing a source of 

 humus so necessary in keeping up proper fertility and 

 texture of the sandy soil of Florida. 



E. N. Beasonbe. 



CITRVLLTTS (from Citrus). GucurUUcem. The ge- 

 nus which includes the Watermelon. Cogniaux, the 

 latest monographer (DC. Monogr. Phaner. 3), recog- 

 nizes three species, all of the Old World, with the larg- 

 est dispersion in Africa. Plant monoecious, the two 

 kinds of fls. solitary in the axils of the Ivs. : fls. with a 

 short, bell-like calyx tube and a deeply 5-cleft, yel- 

 low corolla. C, vulgd,ris, Schrad., is the Watermelon 

 (which see), native to tropical and south Africa. C. 

 Coloo^nthis, Schrad., is the Colocynth, extract from the 

 fruit of which furnishes a well-known purgative drug. 

 It is native to the Mediterranean region and tropical 

 Africa. The fruit is small and globular, gourd-like, 

 smooth and partly colored, the flesh very bitter : Ivs. 

 deeply divided. L, H. B. 



ClTRUS (ancient name for Citron). BuiAcem. Oeanqe, 

 Lemon, Citron, etc. Aromatic, glandular shrubs or 

 small trees, mostly thorny: Ivs. alternate, with more or 

 less winged petioles, compound, mainly unifoliolate 

 (appearing as a simple leaf but really compound, as 

 shown by the joint between the petiole and lamina. 

 Fig. 475), in one species trif oliolate : fls. hermaphrodite; 

 calyx cupulate, 3-5-toothed ; petals 4-8, linear-oblong, 

 thick, glandular, imbricated in the bud ; stamens nu- 

 merous, 20-60, occasionally only 5 ; filaments more or 

 less united ; disk cushion-shaped ; ovary compound, 

 composed of 5 to many united carpels, with a single 

 style and stigma, and central axial placenta; ovules 4-8 

 in each carpel, arranged in two rows : fr. a round, ob- 

 long or pear-shaped berry with leathery rind, containing 

 numerous oil glands and juicy, aromatic pulp : seeds 

 white, exalbuminous, with leathery coats, frequently 

 containing 2 or more embryos. Native of tropical and 

 subtropical Asia. Several species are extensively culti- 

 vated and have given rise to numerous cultivated forms. 

 The so-called navel oranges have a second series of 

 cells developing in the center of the fr., this being an 

 incidental variation (Of. Fig. 470). See Citron, Lemon, 

 Lime, Orange, Pomelo. 



A. PSEUDO-.fflGrLB. — J-us. trifoUolate, deciduous, with 

 elliptical, dentate or crenate Itts.: fls. white, l-2in 

 the axil of each leaf, opening before the Ivs. appear 

 in spring; petals spatulate: ovary and disk 

 hairy. 

 trifoli&ta, Linn. (C. trlptera, Desf. ^gle sepihria, 

 DC). Tbifohate Orange. Figs. 477, 478, 479. A 

 small tree armed with very strong, stiff thorns, 1-1 K in. 

 long: fr. golden yellow, about the size of a walnut, cov- 

 ered with short hairs ; pulp rather dry, sour and bitter. 

 Jap., and cult, widely in the United States. R.H. 1869, 

 p. 15; 1877, p. 73; 1885:516; 1886, p. 533. Gn. 46:980 

 and p. 273. Mn. 3 : 101. - The fr. of the Trifoliate Orange 



475. Leaf of Orange. 



is worthless as a whole, but is sometimes used for pre- 

 serves. The plant is largely used for hedges, for which 

 it is well adapted, forming a close, compact growth that 

 nothing can penetrate. It is also used as a hardy stock 

 on which to bud certain oranges and lemons, particu- 

 larly the Satsuma and Kumquat. It is said to have the 

 effect of somewhat dwarfing the more robust orange va- 



rieties budded on it, and of making them more hardy by 

 rendering them dormant earlier in the fall, and retard- 

 ing them from starting early in the spring. The Tri- 

 foliate Orange is hardy as far north as Philadelphia and 

 New York. It is propagated by seeds, which are very 

 numerous. Hybrids have been made between this and 

 the common orange. The Trifoliate Orange is frequently 

 listed in trade catalogues under the names Limonia tri- 

 foliata and Triphasia aurantiola. These are tender, 



476. Normal orange on the right ; abnormal or navel orange 

 on the left, shov^ring the adventitious cells in the center. 



tropical shrubs, and should not be confused with the 

 hardy C, trifoliata. 



AA. 'Euoi'rsuB.—Lvs. ^mifoUolate, evergreen : petals 

 oblong: ovary and disk glabrous. 



AurAntium, Linn. (C. vulgaris, Risso). Oeanoe. 

 Figs. 476, 480. A small tree or shrub : young shoots light 

 green, glabrous : Ivs. elliptical or ovate, acute, obtuse, 

 or acuminate; petiole narrowly or broadly winged : fls. 

 hermaphrodite, pure white: fr. oblate-spherical or ellip- 

 tical, not mamlllate. 



Var. am&ra, Linn. [C. Bigarcidia, Duham. ). Sour, 

 Bitter, or Seville Orange. Lvs. deep green, ovate, 

 pointed, very aromatic ; petiole broadly wing-mar- 

 gined: fls. white, sweet-scented: fr. round, dark orange, 

 frequently with tinge of red, very aromatic ; rind some- 

 what rough ; pulp sour and bitter. Southeastern Asia, 

 and cult, iu tropical and subtropical regions throughout 

 the world. — There are very few cultivated sorts of this 

 variety or subspecies grown in the United States, and 

 of these only the two following are well kr own : Sour 

 ("sour orange") : Fr. deep orange or orange-red ; pulp 

 very sour. This is grown very extensively as a stock on 

 which to bud varieties of the sweet orange, lemon, 

 pomelo, etc. Very valuable as a stock because resistant 

 to the serious disease mal-di-gomma or foot-rot. — Bitter 

 Sweet : Fr. of same external appearance as the Sour 

 Orange but mildly acid and pleasant to the taste. Culti- 

 vated mainly for home use. The Sour Orange was evi- 

 dently introduced into Florida very early by the Span- 

 iards, and escaped from cultivation, becoming esiab- 

 lished as a wild species here and there throughout the 

 peninsular portion of the state. In this wild state it was 

 limited to moist lands near streams and lakes, in the so- 

 called hammocks ; and in some instances grew abun- 

 dantly among the larger forest trees, over areas of 100 

 acres or more. The fls. of this var. Amara are slightly 

 bitter, and are the officinal Folia aurantii or Folia citri 

 vulgaris. An ethereal oil is manufactured from the fls., 

 young sprouts and unripe fr. The pleasant-smelling, 

 bitter Bigaradia oil is taken from the rind of the ripe f r. 

 Large quantities of oil for perfume are manufactured 

 from the fls. in southern France. The fr. is used for 

 marmalade, and makes a very refreshing drink known in 

 Florida as "orangeade." 



Var. Bergimla, Wight. & Arn. Bergamot" Orange. 

 A bush or small tree : lvs. oblong ; petiole wing-mar- 



