Jan. 27, 1923 
Citrangequats and Limequats 
2 33 
barrier, despite its promising features of canker-resistance and extreme 
vigor. * * * * * 6 The recent discovery, however, that cuttings of the citrangequat 
may be rooted readily by the use of new methods, has been so encouraging 
that extended trials of this plant as a stock are now under way. By the 
use of rooted cuttings, practically a full year's time may be saved in 
growing stocks to budding size, an advantage certainly sufficient to 
offset any additional trouble and expense for greenhouse equipment. 
A combination of bottom heat, about 90° F, with humidity maintained 
at a high point, 8o° to 90°, and with air temperature lower than that of 
the soil, 70° to 8o°, is essential to the best results. 7 With good control 
of all these factors, small twig cuttings with leaves attached may befooted 
within a few weeks—in less time, in fact, than it usually takes for seed 
to germinate. 
Plate 3 shows two of these cuttings and the original seedling plants be¬ 
side them, with the stubs visible where the cuttings were removed. 
These cuttings were photographed only 4X months from the time they 
were placed in the rooting bed and are fine specimens of a large lot rooted 
in February, 1921. The seedlings were 18 months old. An interesting 
point in this connection is the fact that while the citrangequat roots so 
freely the three parent species utilized in creating the hybrid (the sweet 
orange, trifoliate orange, and kumquat) commonly fail to root under the 
same conditions. 
By the use of rooted cuttings, certain advantages are secured well 
worth consideration. First, the time saved has already been mentioned; 
second, through vegetative propagation uniformity of vigor is secured 
which is highly desirable and cannot ordinarily be expected through 
the use of seedlings; and, third, it has often been noted in the propagation 
of cross-bred plants that there is a vigor of growth in the first generation 
seedlings not so apparent in succeeding generations of self-pollinated 
plants. This vigor can be utilized to best advantage by the rooting of 
cuttings from especially vigorous individuals. 
Buds of Satsuma and other citrous fruits grow readily on citrangequat 
stocks, but tests under field conditions will be necessary before definite 
conclusions can be drawn. While such tests have been under way now 
for several years, more time will be necessary in order to secure trust¬ 
worthy conclusions as to the effect of the stock on the quality, size, 
and season of fruit crops, as well as hardiness and other factors of practical 
importance. 
Regardless of the possible utilization of the Thomasville citrangequat 
as a stock, its obvious value as a hardy, canker-resistant fruit tree for 
home use makes it desirable to give it a distinctive name and publish 
a detailed description. 
• The character of this hybrid as regards seed content seems to be dependent largely on the possibility of 
its receiving pollen from other seedy varieties of Citrus. In many places where grown by itself or along 
with seedless varieties (such as Satsuma, having little or no viable pollen) the fruit is practically seedless, 
while in other plantings where mixed with seedy varieties, seeds are usually found averaging six or eight 
to the fruit. 
The Thomasville citrangequat, like many other hybrids between widely differing species of the Citrus 
group, reproduces itself unchanged from seed. This means that it is in reality a sterile hybrid and the 
embryo found in the seed is developed from the tissues of the mother plant and of course shows no effect of 
the pollen used in fertilizing the flower. 
7 The method used was developed in January and February, 1921, by Mr. Eugene May, jr., plant propa¬ 
gator of the Office of Crop Physiology and Breeding Investigations, and is an adaptation of the rooting 
methods devised by Mr. Edward Goucher, of the Office of Foreign Seed and Plant Introduction, Bureau 
of Plant Industry, United States Department of Agriculture, for the rooting of small twig cuttings of the 
Lychee. (Goucher, Edward, rooting eychee cuttings by means op a high temperature and high 
humidity process. In Groff, George Weidman. the lychee and dungan, Appendix 8, p. 157-159, 
New York, London, and Canton, China, 1921). 
