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In previous lectures I have mentioned that I have saved the seeds of the mutants whenever possible, and have always obtained repetitions of the prototype only. Reversions are as absolutely lacking as is also a further development of the new type. Even in the case of the inconstant forms, where part of the progeny yearly return to the stature of lamarckiana, intermediates are not found.
The giant evening-primrose, though not taller in stature than O. lamarckiana, deserves its name because it is so much stouter in all respects. The stems are robust, often with twice the diameter of lamarckiana throughout. The internodes are shorter, and the leaves more numerous, covering the stems with a denser foliage.
It would be worth while to see whether the climate of California, where neither O. lamarckiana nor O. biennis are found wild, would not exactly suit the requirements of the new species rubrinervis and gigas. A fixed hybrid between O. cruciata and O. biennis constituting a species has been in cultivation for many years.
The cultures of De Vries are descended from these commercial seeds, but the Swedish race of Lamarckiana, as well as those of English gardens, differ in several features and must have come from another source or been modified by crossing with grandiflora.
Or is it perhaps concealed among the throng, being distinguished by no peculiar character? If our gigas and rubrinervis were growing in equal numbers with the lamarckiana in the native field, would it be possible to decide which of them was the progenitor of the others?
O. cruciata grows in the Adirondack Mountains, in the states of New York and Vermont, and seems to be abundant there. It has been introduced into botanical gardens and yielded a number of hybrids, especially with O. biennis and O. lamarckiana, and the narrow petals of the parent-species may be met with in combination with the stature and vegetative characteristics of these last named species.
There is no danger that lamarckiana might die out from the act of mutating, nor that the mutating strain itself would be exposed to ultimate destruction from this cause. In older swarms, such as Draba or Helianthemum, no such center, around which the various forms are grouped, is known. Are we to conclude therefore that the main strain has died out?
But, on the contrary, the atavists, which are here the individuals with the stature and the characteristics of the lamarckiana, have become lamarckianas in their hereditary qualities, too. If their seed is saved and sown, their progeny does not contain any scintillans, or at least no more than might arise by ordinary mutations.
More than twenty types could be distinguished and seeds were saved from a number of them, in order to ascertain whether they are constant, or whether perhaps a main stem in a mutating condition might be found among them. If this should prove to be the case, the relations between the observed forms would probably be analogous to those between the O. lamarckiana and its derivatives.
The plants themselves always remain small, never reaching the stature of the ancestral type. They are likewise much less branched. They can easily be cultivated in annual generations, but then do not become as fully developed and as fertile, as when flowering in the second year. The flowers have the same structure as those of the lamarckiana, but are of a smaller size.
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