84 CALIFORNIA CITRUS CULTURE. 



winged, compound though usually unifoliate ; the joint between petiole 

 and leaf shows that the apparent simple leaf is really compound ; in one 

 species trifoliate; flowers, pink or white, sweet-scented, hermaphrodite, 

 calyx cupulate, three to five toothed ; petals, four to eight, linear oblong 

 imbricated in the bud; stamens, twenty to sixty, rarely only five; fila- 

 ments more or less united; ovary compound, with five to many united 

 carpals, one style and stigma, ovules, five to eight in each carpal in two 

 rows ; fruit a berry, spherical, oblong or pear-shaped with thick leathery 

 rind containing numerous oil cells, pulp, juicy, aromatic ; juice con- 

 tained in curiously formed sacs, the form possessing possibly specific 

 importance. Supposed origin of this genus is Cochin China or the 

 Malayan Islands. 



Citrus trifoliata Linn. 



In its trifoliate deciduous foliage this species from Japan is peculiar. 

 It is a shrub or small tree, very thorny (Fig. 56) with spherical yellow 

 fruit and valuable commercially only as a hedge plant and for stock 

 on which to bud the commercial orange and lemon. It is thought to 

 dwarf the latter and may be more hardy than other stock. As pre- 

 viously stated, sour stock is now thought to be greatly preferable. It 

 endures more cold, and so Dr. H. J. Webber has originated hybrids 

 between this and the orange in hope of securing the frost resistance 

 of the trifoliata and something of the excellence of the orange. 



Citrus aurantium Linn. var. amara Linn. 



This orange, known as Bigaradia (sour or bitter orange), also the 

 Seville orange, is thought to be the original of all our oranges. The 

 leaf is broadly winged, the flowers sweet-scented and the fruit spherical. 

 It was brought early to Florida by the Spaniards and ran wild. The 

 fruit (Fig. 57) is too bitter and sour for commercial purposes, but is 

 sometimes used for marmalade. The seeds are large and prized, as 

 the seedlings are thought by some to be more hardy and vigorous than 

 are those from other seeds, and it is also said to stand neglect better, 

 and to be more resistant to gum diseases. If the stock does influence 

 the scion or bud, it is not obvious in this case, as the fruit seems not 

 inferior. Mr. Lelong thought the Bigaradia inferior as stock to the 

 sweet orange, for he says: "The trunks are not as large as those on 

 sweet stock and show less expansion of root system." Our best author- 

 ities today favor strongly sour orange stock. There is considerable 

 variation in these sour oranges. Lelong mentioned ten marked strains. 

 Dr. "Webber says there are only two, the bitter orange, prized as stock 

 for budding, and the bitter-sweet, which is more pleasing to the taste. 

 It is claimed by some that this is a well marked species, and the fact 



