68 
RUTACEAE 
drupes red, size of a pea.—S. Am. species, commonly planted as a street- 
tree, especially in S. Cal. 
RUTACEAE. RUE FAMILY 
Herbs, shrubs or trees. Leaves usually alternate, simple or compound, 
glandular with pellucid dots. Flowers regular. Sepals 4 or 5. Petals 
4 or 5. Stamens 8 to 10 or more. Ovary superior, 2 to 5-celled, seated 
on a glandular disk. Fruit a capsule or samara, or fleshy and indehiscent. 
—About 900 species, mostly tropical. The native representatives are 
Thamnosma montana Torr. & Frem. (Turpentine Broom), a low desert 
shrub with alternate simple leaves and purple flowers; Cneoridium dumo- 
sum Hook, f., a bush of San Diego Co., with opposite simple leaves and 
drupe-like fruits, and Ptelea baldwinii T; & G. (Hop-tree), a shrub of the 
Coast Ranges with 3-foliolate leaves and fruit a samara. 
1. CITRUS L. 
Small evergreen more or less spiny trees or shrubs. Leaves uni- 
foliately compound with winged or margined petioles. Flowers white, 
fragrant. Stamens numerous, the filaments united at base into several 
bundles. Fruit a many-seeded, large berry (hesperidium) with a thick 
rind. (Ancient name of a fragrant African wood, afterwards trans¬ 
ferred to the citron.) 
Petals white above, tinged with red below; fruit mostly elongated.... 1. C. medica. 
Petals white on both surfaces; fruit commonly roundish. 
Petioles broadly winged ; branchlets and under side of leaves downy-pubes- 
cent...2. C. decumana. 
Petioles slightly winged; branchlets and leaves glabrous.3. C. sinensis. 
1. C. medica L. Citron. Shrub or small tree with large oblong 
leaves; leaves apparently not jointed between blade and petiole; petioles 
wingless; fruit oval or oblong, bluntly apiculate, lemon-yellow; rind thick, 
fragrant, coarsely roughened or furrowed.—Cult, from China. Var. 
limonum. Lemon. Small tree; leaves with an obvious joint between 
blade and petiole; petiole narrowly margined; fruit distinctly elongated, 
the rind not rough, with an abundant and acid juice. Var. limetta 
(Risso.) Engl. Lime. Small tree; leaves small; petioles narrowly 
winged; flowers small; fruit small, greenish-yellow, very acid.—Cult, 
from India. 
2. C. decumana Murr. Grapefruit. Pomelo. Shaddock. Large 
tree; petioles broadly winged; flowers large; fruit large, pale lemon- 
yellow when ripe; pulp acid.—Cult, from the tropics of Asia. It is called 
grape-fruit because the fruits are borne in clusters, but the name also 
has significance by reason of the delicious juice which recalls that of the 
Muscat of Alexandria. 
3. C. sinensis Osbeck. Common or Sweet Orange. Medium-sized 
trees with large ovate leaves ; petioles narrowly winged, articulated both 
with the blade and the stem; style deciduous; fruit globose to sub-glo¬ 
bose, golden yellow; pulp usually sweetish.—Cult, from Asia. Leading 
horticultural varieties in Cal. are the Washington Navel and Valencia. 
