WORK OF THE UNITED STATES DEPARTMENT, &c. 129 
it is, however, sometimes used for preserves. It is very late in starting 
in the spring, the flowers appearing before the foliage, and not even 
showing till the Common Orange is nearly out of bloom. It is thus 
regularly about a month later in starting in the spring than the common 
Orange and other citrous fruits, and is never caught by late frosts. Again 
in the fall it ripens it fruits early, and becomes dormant a considerable 
period before the Common Orange. The Common Orange, on the other 
hand, is an evergreen unifoliolate tree growing more or less during the 
entire winter unless checked by severe cold. Judging from the results 
which have been obtained with other plants it seems perfectly possible by 
crossing and recrossing the Orange with the hardy trifoliata to ultimately 
secure a hybrid combining the fruit characters of the former with the 
hardiness of the latter. 
Many instances are recorded where hybrids have been obtained com- 
bining certain characters of the parents, but only a few are known to the 
writer where increased hardiness has been secured. According to Verlot,* 
the forms of Rhododendron arborewm are rendered hardier by crossing 
with Ff. catawbiense. Macfarlane has called attention to the hardiness of 
a hybrid between the hardy Montbretia Pottsw and Tritonia aurea, which 
latter is easily injured by cold. He says, referring to the winter of 1891— 
92: ‘The corms of the first (Montbretia) appear scarcely to have been 
injured. Those of the hybrid have been largely killed off, at least to the 
extent of sixty per cent., while 777tonia, never hardy in exposed ground, 
has survived only where it is planted against, and can creep along, the 
outer side of a hothouse wall.’”’r A second case is also described by 
Macfarlane where a hybrid between a hardy and a tender species is 
intermediate in hardness between the two. He says: ‘“‘ Philesia buxifolia 
is a hardy plant, and resists well our winter colds. Lapageria rosea 
requires the temperature of a cold hothouse to flourish, while the bybrid 
succeeds if kept protected from frosts and the more cutting winds. In 
the southern counties of Britain it lives and flowers out of doors.’+ A 
similar case of increased hardiness secured by hybridisation is cited by 
Manda: ‘By crossing Rosa Wichuraiana with greenhouse Teas the 
result is astonishing, as the plants are not only hardy but retain their 
foliage during the winter. Thus a new race of evergreen Roses has been 
added to our collection, and promises to be the beginning of a new and 
useful class.’ 
The change desired in the Orange is not so great as one is at first 
inclined to think. If by infusing a slight portion of the trifoliata blood 
into the Orange we can somehow modify its habits of growth and cause 
it to remain more dormant through the winter, and later into the spring, 
we have accomplished our aim, and this, we think, is perfectly possible. 
The production of Grape hybrids having the resistance to Phyloxera 
of certain of the American species such as Vitis riparia and V. rupestris, 
* Verlot, Jean Baptiste, “Sur la Production et la Fixation des Variétés dans les 
Plantes d’Ornement,” cited in Bailey’s Plant Breeding, p. 145. 
+ Macfarlane, Dr. J. M., ‘A Comparison of the Minute Structure of Plant Hybrids 
with that of their Parents, and its Bearing on Biological Problems,” Trans. Royal Soc. 
Edinburgh, vol. xxxvii. Pt. I. No. 14, p. 258. 
{ Manda, W. A., “ Hybrid Wichuraiana Roses,” Gardening, vol. vi. No. 145, 
Sept. 15, 1898, p. 9. 
K 
