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Of varieties with a negative attribute, or real retrograde varieties, I have found three, all of them in a flowering condition in the field. I have given them the names of laevifolia, brevistylis and nanella. The laevifolia, or smooth-leaved variety, was one of the very first deviating types found in the original field. This was in the summer of 1887, seventeen years ago.
They obey the same general laws, become active under similar conditions, some of them being more easily awakened than others. The germs of the oblonga, lata and nanella are especially irritable, and are ready to spring into activity at the least summons, while those of gigas, rubrinervis and scintillans are far more difficult to arouse.
These three new forms are therefore considered to constitute only retrograde steps, and no advance. This conclusion has been fully justified by some crossing experiments with brevistylis, which wholly complies with Mendel's law, and in one instance with nanella, which behaves in the same manner, if crossed with rubrinervis.
This is especially evident in the case of lata and nanella, which appeared in the first year of the pedigree culture and which since have been repeated yearly, and have been seen to arise by mutation also during the last season . Only gigas appeared but once, but then there is every reason to assume that in larger sowings or by a prolongation of the experiments it might have made a second appearance.
Briefly considering the different forms, we may state that the full experimental proof has been given for the origin of gigas and rubrinervis, for albida and oblonga, and even for nanella, which is to be considered as of a varietal nature; with lata the decisive experiment is excluded by its unisexuality. laevifolia and brevistylis were found originally in the field, and never appeared in my cultures.
The same forms that are produced most often by the parent-family are also most ordinarily met with among the offspring of the shiny evening-primrose. They are oblonga, lata and nanella.
The three first generations were biennial, but the five last annual. Gener: O.gig. albida obl. rubrin. Lam. nanella lata. scint. It is most striking that the various mutations of the evening-primrose display a great degree of regularity. There is no chaos of forms, no indefinite varying in all degrees and in all directions.
Albida, nanella and rubrinervis appeared in large numbers, and even scintillans, of which I had but a single plant in the previous generation, was repeated sixfold. New forms did not arise, and the capacity of my strain seemed exhausted.
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