138 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
Resistance to Disease—The Sour Orange (C. awrantiwm amara) has 
been found by extended observations to be largely immune to the so-called 
“ blight,’’ which is probably the worst Orange disease known in Florida. 
Hoping to secure desirable sorts of sweet edible Oranges immune to this 
disease, the Orange was crossed with pollen of the “ Bitter Sweet,’ 
which is the best variety of the Sour Orange. The twenty-seven hybrids 
of this parentage are the most variable of any set or combination of 
citrous hybrids which we have obtained. Some have leaves almost 
exactly like the Bitter Sweet, others almost exactly like the Orange, 
others present a totally distinct shape of leaf from either parent. Of 
these twenty-one resemble in main the mother, and six in main the male 
parent. 
Other hybrids were made for various minor improvements, but it is 
not desirable to discuss them further here. 
Summary of Resemblances of Citrous Hybrids.—In the hybrids of 
the widely distinct species the seedlings divide themselves plainly into 
two classes: (1) Those resembling the mother parent entirely, so far as 
could be determined ; and (2) those intermediate in character. 
Total number | Number re- | Number inter- 
Parentage of seedlings ceva mother mediate 
Trifoliata 2 x Sweet Orange ¢ : | 40 | 29 11 
Sweet Orange 9 x Trifoliata 3 Sel 14 | 9 | 5 
Tangerine 9 x Trifoliata 3 é | 12 ial | 1 
In the hybrids of closely related species, such as Orange x Pomelo 
and Orange x Tangerine, the intermediate nature of the hybrids, if they 
are intermediate, cannot be easily distinguished. In foliage and other 
characters, so far as exhibited previous to fruiting, they seem to resemble 
very closely either the mother or father parent. The following table will 
show the propegont of their resemblance :— 
j 
| Number resem- 
Total number Number resem- 
Parentage of seedlings | bling mother | bling father 
Tangerine 9 x Sweet Orange ¢ : : 286 | 247 39 
Sweet Orange 9 x Tangerine o : : 15 69 6. 
Pomelo 2 x Tangerine g. A ; : 116 abl 5 
Pomelo 9 x Sweet Orangeg . : ; 126 106 20 
Sweet Orange 2 x Pomelo¢ . ; ; 103 95 8 
Sweet Orange 9 x Bitter Sweet gd . 27 21 6 
West Indian Lime 2? x Sicily Lemon ¢ . if) 9 2 
Sicily Lemon 9 x West Indian Lime @ . 9 | 9 0 
West Indian Lime 2 x Pomelo ¢g . d 4 4 0 
PINEAPPLE HYBRIDISATION. 
The principal problems here presented are to secure—l, better 
shipping sorts; 2, smooth-leaved sorts; 8, sorts resistant to disease ; 
and 4, sorts having larger fruits of better quality. These objects 
have been kept clearly in view in all of our work. Pineapples, as is well 
known, are almost totally seedless. Among the fruits which reach the 
American markets from the Bahamas, West Indies, and Florida it is 
