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 
