Some of these are very beautiful, and render it probable that by intercrossing with the older species still further difficulties will be presented in the way of identification. [Please select]
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But when we go beyond the limits of the same species, free intercrossing is barred by the law of sterility. [Please select]
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349; intercrossing of strawberries, i, 351, 352; broad variety of the cock's comb, i. [Please select]
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When several breeds have once been formed, their intercrossing aids the progress of modification, and has even produced new sub-breeds. [Please select]
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Before giving the few recorded cases of forms, which must be ranked as varieties, being in some degree sterile when crossed, I may remark that other causes sometimes interfere with varieties freely intercrossing. [Please select]
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