United States or Bolivia ? Vote for the TOP Country of the Week !
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.
It is readily granted that such special preparation may occur, because the great numbers in which our dwarf variety of the Oenothera are yearly produced are suggestive of such a condition. On the other hand, the laevifolia and brevistylis mutations have not been repeated, at least not in a visible way.
The leaves of the O. brevistylis are more rounded at the tip, but the difference is only pronounced at times, slightly in the adult rosettes, but more clearly on the growing summits of the stems and branches. By this character, the plants may be discerned among the others, some weeks before the flowers begin to show themselves.
Harmless or even slightly useless ones have been seen to maintain themselves in the field during the seventeen years of my research, as proved by Oenothera laevifolia and Oenothera brevistylis. Most of the others quickly disappear. This failure of a large part of the productions of nature deserves to be considered at some length.
The unevenness of the surface of the leaves may increase as in lata, or decrease as in laevifolia. The tendency to become annual prevails in rubrinervis, but gigas tends to become biennial. Some are rich in pollen, while scintillans is poor. Some have large seeds, others small. Lata has become pistillate, while brevistylis has nearly lost the faculty to produce seeds.
It is simply impossible to tell from which individual plants they have been derived. The laevifolia and the brevistylis have been found almost every year, the first always recurring on the same spot, the second on various parts of the original field. It is therefore allowable to assume a common origin for all the observed individuals of either strain.
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.
Varieties differ from their species clearly in one point, and this is either a distinct loss, or the assumption of a character, which may be met with in other species and genera. laevifolia is distinguished by the loss of the crinkling of the leaves, brevistylis by the partial loss of the epigynous qualities of the flowers, and nanella is a dwarf.
They lack the high stigma placed above the anthers, which in the lamarckiana, by the vigorous growth of the style, extends the calyx and renders the flower bud thinner and more slender. Those of the brevistylis are therefore broader and more swollen. It is quite easy to distinguish the individuals by this striking character alone, although it differs from the parent in other particulars.
On the original field the laevifolia and brevistylis have held their own during sixteen years and probably more, without, however, being able to increase their numbers to any noticeable extent. Others perish as soon as they make their appearance, or a few individuals are allowed to bloom, but probably leave no progeny.
Word Of The Day