Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: June 9, 2025
It occurs in the OEnothera mutant gigas. The origin of it has not been clearly made out, but it must result either from the splitting of each chromosome or from the omission of the chromosome reduction.
Only one or two exceptions could be quoted, as for instance the Oenothera brevistylis, which in its crosses always behaves as a pure retrogressive variety.
Unfortunately they are very sensitive, especially to wet weather. Oenothera gigas and O. rubrinervis, or the giant, and the red-veined evening-primroses, are the names given to two robust and stout species, which seem to be equal in vigor to the parent-plant, while diverging from it in striking characters.
In other words we may state "that current misconceptions as to the extreme range of fluctuating variability of many native species have generally arisen from a failure to recognize the composite nature of the forms in question," as has been demonstrated by MacDougal in the case of the common evening-primrose, Oenothera biennis.
New elementary species are far more rare, but I have discovered in the great evening-primrose, or Oenothera lamarckiana a strain which is producing them yearly in the wild state as well as in my garden. These observations and pedigree-experiments will be dealt with at due length in subsequent lectures.
In no case is the original organ or character, e.g. wings, of the normal Fly first developed and then changed by a gradual continuous process into the new character. It might perhaps be said that this took place in the pupa, but that seems impossible, for the complete wing is not fully developed in the pupa. The same truth is equally apparent in the mutations described in OEnothera.
Leaving the robust novelties, we may now take up a couple of forms, which are equally constants and differentiated from the parent species in exactly the same manner, though by other characters, but which are so obviously weak as to have no manifest chance of self maintenance in the wild state. These are the whitish and the oblong-leaved evening-primroses or the Oenothera albida and oblonga.
I propose to designate both new forms by the varietal name of cruciata, or cruciatum. Oenothera biennis cruciata was found in a native locality of the O. biennis itself. It consisted of only one plant, showing in all its flowers the cruciata marks.
But it is manifest that the original production of the characters of Oenothera gigas was a phenomenon of far greater importance than the subsequent accidental transition of this quality into the active state.
They suggested in fact that Oenothera Lamarckiana was the result of a cross, or repeated crosses, between plants differing in many factors, that the numerous mutations were similar to the variety of different types which are produced by breeding together the grey mice arising from a cross between an albino and a Japanese waltzing mouse in Darbishire's experiment.
Word Of The Day
Others Looking