20 



Dr. Engelmann. 



BUSHBERG CATALOGUE. 



Hybridity. 



justly claimed to be a hybrid, and what only a 

 variety within the limits of some variable spe- 

 cies, and the opinions of different persons may 

 honestly vary on these points. But whoever 

 has studied the great variability of many 

 plants will hesitate long before he calls to his 

 aid the often fanciful help of hybridity in the 

 explanation of doubtful forms. Where species 

 are so well marked as e. g. Labrusca is, it is 

 not difficult to recognize some of its characters 

 in a hybrid off-spring, though the general 

 looks of the questionable plant otherwise may 

 not conform to our idea of Labrusca at all ; but 

 in other cases, where species already stand 

 near one another, the matter becomes much 

 more difficult. But there is another way, 

 unfortunately a very tedious one, to assist 

 in such investigations, viz : to sow the seeds 

 of hybrids and study their offspring ; for it is 

 a fact that seedlings of hybrids are apt to 

 revert to, or at least to approach to, one or the 

 other of the parents. One of the most striking 

 examples of both positions here taken is fur- 

 nished by the well-known Taylor or Bullit 

 grape. The vigorous growth of this form, its 

 thin diaphragms, its glossy, glabrous fol- 

 iage, its small clusters of rather small berries 

 entirely destitute of foxy taste, all seem to 

 point to it as a cultivated variety of JRiparia ; 

 but when we come to examine the tendrils we 

 find that they are irregular ; sometimes inter- 

 mittent, sometimes more or less continuous 

 (I have seen six in succession, which can only 

 point to Labrusca), and just so the seeds differ 

 from Biparia seeds by their great size and their 

 form (see page 13, fig. 3). Now it so happens 

 that Taylor seeds have baen planted by the 

 million in Europe, in order to raise resistant 



stock for grafting, and the general experience is 

 that one cannot find two seedlings in a hund- 

 red alike, and similar to the mother-plant ; 

 some approach the Riparia type, and others 

 show the Labrusca parentage distinctly. 

 Thus, to give only one example, one of such 

 seedlings the now frequently cultivated El- 

 vira is a Taylor seedling with a close approach 

 to Labrusca. 



It would further the study of our Grape- 

 vines considera bly if some of those that have 

 the zeal, the leisure and the opportunity, 

 would institute such experiments with doubt- 

 ful forms. 



Pursuing this interesting subject further, I 

 may add that where nearly allied species grow 

 near together, and bloom about the same time, 

 they are rtnre likely to hybridize than such 

 species that are separated by wide space or 

 different period of flowering. With all these 

 considerations we must not forget that with 

 the innumerable opportunities given every 

 where for hybridization we find comparatively 

 so few spontaneous hybrids in the vegetable 

 world. Hybridization is an abnormal, I may 

 say, an unnatural process, which is usually 

 prevented by countless obstacles. If it were 

 not so, we would meet with more hybrids in 

 our woods and prairies than with genuine spe- 

 cies ; but how rare are they, and what a find 

 it is for a botanist to discover one! And this 

 is the more to be wondered at, because the 

 genital organs of the plants, though mostly 

 united in one flower, are usually so organized 

 that self-fertilization is made difficult, or i& 

 excluded, and that cross-fertilization is the 

 rule. We may put it down as a law that 

 honest nature abhors hybridization. 



