230 
Journal of Agricultural Research voi. xxiii, no. 4 
the lime being the tenderest citrous fruit grown in the United States, 
often being injured by cold even in central or south Florida. The 
hybrids resulting from this cross have been called limequats, and are also 
described here. Fourth, the attempt was made to hybridize the kumquat 
with the lemon, the lemon being almost as tender as the West India 
lime. None of these hybrids have been sufficiently well studied to war¬ 
rant reporting on them as yet. So far as observed they have fruits very 
similar to the limequats described below except that the peel is much 
thicker. 
THOM AS VILLE CITRANGEQUAT 
Among the citrous crosses made at Eustis, Fla., in June, 1909, by the 
senior author, was one in which pollen of the Willits citrange was used to 
fertilize flowers of the oval kumquat (Fortunella margarita) (Lour.) 
Swing. 
Budded plants of the best of the hybrids resulting from this cross were 
sent to a number of cooperators in the southeastern States as soon as it 
was possible to effect propagation. The first plant to bear fruit was 
numbered C.P.B. 480io. 3 Fruits were received at Washington, D. C., 
in November, 1915, produced by a plant of this number that had been 
sent to Mr. P. J. Hjort at Thomasville, Ga., in March, 1913. As this 
hybrid was first fruited at Thomasville, where it was proved sufficiently 
desirable as a fruit for home use to induce Mr. Hjort to propagate it in 
his nursery, it is proposed to call it the Thomasville citrangequat. 
The Willits citrange, the pollen parent, is itself a hybrid resulting from 
crossing the sweet orange (1 Citrus sinensis , Osb.) with the trifoliate orange 
(Poncirus trifoliata (L.) Raf.), the former supplying the pollen which was 
► used on the pistils of the trifoliate orange. 
While this citrange is of fairly good quality and makes an excellent ade, 
the oil of the peel is very bitter and ill-smelling, and a single drop is 
enough to ruin a pitcher of ade. It was hoped by hybridizing the Willits 
citrange with the oval kumquat to overcome this drawback of the citrange 
since the peel of the kumquat is so mild as to be edible, and at the same 
time the juice of the kumquat is pleasantly acid, so that a hybrid between 
it and the citrange would be expected to be suitable for making ade. 
These expectations were fully justified, as is shown below. 
As was noted in the introductory paragraph of this paper, another 
quality that it was hoped to secure in this hybrid was an increased winter 
dormancy over that shown by the citrange. The kumquat possesses 
winter dormancy of a very high degree and is able to go through long 
spells of warm weather without starting new growth. The new growth 
of practically all citrous fruits is, of course, easily injured by even 
moderate frosts. Although the Willits, like other hybrids of the trifoliate 
orange, is extremely hardy when in a dormant condition, it is not able to 
stand long periods of warm weather in winter without starting new 
growth. The new citrange-kumquat hybrid, as was hoped, is superior to 
the Willits in all-around hardiness and shows a distinctly higher winter 
dormancy. Being the result of crossing a citrange with a kumquat, the 
new hybrid was called a citrangequat. 
The citrangequat seedlings showed from the start, phenomenal vigor 
and in fact made the most rapid and continuous growth of all the nu- 
• The abbreviation C.P.B. is used for the name of the Office of Crop Physiology and Breeding Investiga¬ 
tions of the Bureau of Plant Industry, United States Department of Agriculture. All the numbers cited in 
this paper are of this series. 
