RUE FAMILY (RUTACEAE) 



99. Toronja, grapefruit 



Grapefruit is recognized among the citiiis fruit 

 trees by: (1) the large round fruit, which is pale 

 yellow at maturity, 31/2-5 inches in diameter, 

 smooth, with flesh usually light yellow, sometimes 

 pink, the taste sweet and acid and bitter combined ; 

 (2) fragrant large white flowers 1-1% inches 

 across the 4 petals; and (3) leaves elliptic, rounded 

 at both ends (or blunt-pointed at apex) and peti- 

 ole usually broadly winged. 



A small aromatic evergreen tree becoming 15-20 

 feet high and G inches in trunk diameter, some- 

 times larger, with rounded spreading crown of reg- 

 ular branches. The bark is smooth gray brown, 

 inner l)ark light yellow and slightly bitter. The 

 green twigs usually have short slender and flexible 

 spines single at nodes, the leaves also alternate. 

 Young twigs and leaves are hairless or nearly so. 



The petiole is 14-I inch long, the wing i4-i/^ 

 inch wide. Blade is 3-6 inches long and l%-3 

 inches wide, jointed to petiole, with many minute 

 rounded teeth at edges, slightly leathery, and with 

 numerous tiny gland dots, above shiny cUirk green, 

 and beneatii dull light green. 



Flowers are solitary or 2-6 in a lateral cluster 

 (raceme). The cup-shaped calyx is irregularly 

 5-toothed, about Y^q inch high and 14 indi or more 

 across; there are 4 oblong white fleshy petals % 

 inch or more in length; 20-25 stamens united into 

 tube in lower part ; and pistil on a disk with round 

 11-14-celled ovary. 



The fruit (berry or hesperidium) has a whitish 

 peeling ■%«-% inch thick. Walls of the flesh are 

 bitter. The numerous whitish elliptic pointecl 

 seeds are about 1/2 inch long. Flowering in the 

 spring and fruiting in the fall, the mature fruits 

 pereisting until May. 



The sapwood is whitish to light yellow, and the 

 heartwood light yellow to yellowish brown. The 

 hard, fine-grained wood with growth rings clearly 

 defined is used chiefly for fuel. 



Grapefruit, a breakfast favorite, is marketed in 

 Puerto Rico eitiier fresh or as canned sections or 

 juice. The tree is an attractive ornamental and 

 honey plant as well as fruit tree. 



Citrus paradisi Macfadyen* 



This is one of the commonest citrus species in 

 Puerto Rico, being grown in plantations, chiefly 

 in the moist coastal region. Formerly it was the 

 most important fruit gi-own commercially on the 

 island for shipment in fresh form to the United 

 States. Now the plantations are mostly aban- 

 doned because competition destroyed the export 

 market. Scattered trees are to be found in the 

 moist limestone and lower mountain regions. Also 

 in the Virgin Islands. 



Range. — Apparently of relatively recent origin 

 in cultivation in the West Indies and not found 

 wild in Asia. Planted extensively in subtropical 

 areas of southern United States in Florida, Texas, 

 Arizona, and California. Also grown through 

 West Indies, from Mexico to South America, and 

 in the Old World tropics. 



Other common names. — toronja (Spanish) ; 

 grapefruit (Central America) ; greifruta (Colom- 

 bia) ; grapefruit (United States, English); cha- 

 deque (Haiti) ; pamplemousse, grapef niit (Guade- 

 loupe) ; gi-apefruit (Dutch West Indies). 



Botanical synonym. — Citrus maxima (Burm.) 

 Merr. var. uvicarpa Merr. & Lee. 



By some authoi-s the grapefruit is placed as a 

 variety of pununelo, shaddock, or pomelo. Citrus 

 grandis (L.) Osbeck* {C. maxima (Burm.) Merr., 

 C. denimnna (L.) L.). The latter has larger 

 thick-skinned fruits 5-6 inches in diameter or 

 slightly pear-shaped, with the juicy particles large 

 and easily separable, large rough yellowish seeds, 

 larger leaves with broadly winged heart-shaped 

 petioles, and very large flowers. 



It is thought that grapefniit originated in the 

 West Indies as a mutation of pummelo or possible 

 hybrid of that species with sweet orange. Ap- 

 parently it was fii-st described in 1750 as the for- 

 bidden fruit of Barbados. In 1814 the English 

 name grapefruit first appeared in a Jamaican 

 book, which attributed the derivation to the re- 

 semblance in flavor to the grape. The species was 

 named botanically from Jamaica in 1830. 



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