These coloured hybrids were originated by M.
In the first place, the so-called internal causes of disease is probably a mere phrase covering our ignorance of the factors at work, and although a certain convenience attaches to the distinction between those cases where tender breeds of plants apparently exhibit internal predisposition to suffer more readily than others from parasites, low temperatures, excessive growth, &c.as is the case with some grafted plants, cultivated hybrids, &c.the mystery involved in the phrase internal causes only exists until we find what action of the living or nonliving environment of the essential mechanism of the plant has upset its equilibrium.
Having obtained a first hybrid generation, he allowed the hybrids to self-fertilize, and recorded the result in a large number of instances (a thousand or more) as to the number of individuals in the first, second, third and fourth generations in which the character selected for experiment made its appearance.
The aboriginal stock of the Uganda Protectorate is undoubtedly the pigmy-prognathous, which has gradually been absorbed, overlaid or exterminated by better developed specimens of the Negro sub-species, or by Negro-Caucasian hybrids from the north and north-east.
Hybrids are also common, the canary breeding freely with the siskin, goldfinch, citril, greenfinch and linnet.
The hybrids thus produced are almost invariably sterile.
Osaria, auxaria, a bundle of osier or willow twigs), the common term under which are included the various species, varieties and hybrids of the genus Salix, used in the manufacture of baskets.
The occurrence of hybrids in nature explains the difficulty experienced by botanists in deciding on what is a species, and the widely different limitations of the term adopted by different observers in the case of willows, roses, brambles, &c. The artificial process is practically the same in hybridization as in cross-fertilization, but usually requires more care.
Hybrids are sometimes less fertile than pure-bred species, and are occasionally quite sterile.
Some hybrids, however, are as fertile as pure-bred plants.
So markedly is this the case with hybrids that in a few generations all traces of a hybrid origin may disappear.
Numerous hybrids have been raised, varying in colour from creamy white to salmon, pink, yellow, red and orange.
Amoena, amoena spectabilis, magnifica, paronychioides major aurea and amabilis; Alyssum maritimum variegatum; some of the dwarf varieties of Antirrhinum majus; Arundo Donax variegata; Begonias; Calceolarias; Cannas; Centaurea ragusina; Clematises, of which the hybrids of the Jackmanni type are best; Dahlia variabilis, and the single-flowered forms of D.
Of late years not only have many fine hybrids been raised artificially between various species, but some remarkable bigeneric hybrids (between what are considered two distinct genera) have also been produced (indicated in the list below by *).
Egtfally great gaps, however, may exist between males and females, between climatic phases or summer and winter forms. The attempt to find a physiological criterion has similarly failed; many forms that have been universally accepted as true species produce fertile hybrids (see Hybridism).
From the variety Bohea, or from hybrids of descent from it, came the China teas of former days and the earlier plantings in India grown from imported China stock.
In the first ten years of attempting to make better hybrids, Borlaug's group made more than six thousand crossings of wheat.
Some thought it was part flying squirrel or some other wild animal, which is not impossible, for, according to naturalists, prolific hybrids have been produced by the union of the marten and domestic cat.