Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: June 20, 2025
One is the mutability of Lamarck's primrose, and the second is the immutable condition of quite a number of other species. Among them are some of its near allies, the common and the small flowered evening-primrose, or Oenothera biennis and O. muricata. From these facts, a very important question arises in connection with the theory of descent.
These had the characters of the muricata in their narrow leaves, but the elongated spikes and relatively large flowers of the hirtella parent, and remained true to this type, showing only slight fluctuations and never reverting or segregating the mixed characters.
The most obvious characteristic marks are afforded by the flowers, which in O. muricata are not half so large as in biennis, though borne by a calyx-tube of the same length. In this respect the hybrid is like the biennis bearing the larger flowers. These may at times seem to deviate a little in the direction of the other parent, being somewhat smaller and of a slightly paler color.
I have crossed another elementary species, the Oenothera hirtella with some of my new and with some older Linnean species, and got several constant hybrid races. Among these the offspring of a cross between muricata and hirtella is still in cultivation. The cross was made in the summer of 1897 and last year I grew the fourth generation of the hybrids.
In the case of Oenothera muricata x biennis the differentiating units reduce the fertility to a low degree, threatening the offspring with almost complete infertility and extinction. But then we do not know whether these characters are really units, or perhaps only seemingly so and are in reality composed of smaller entities which as yet we are not able to segregate.
The parents were the common evening-primrose or Oenothera biennis and of its small-flowered congener, Oenothera muricata. These two forms were distinguished by Linnaeus as different species, but have been considered by subsequent writers as elementary species or so-called systematic varieties of one species designated with the name of the presumably older type, the O. biennis.
As a further consequence the O. biennis opens on the same evening only one, two or three flowers on the same spike, whereas O. muricata bears often eight or ten or more flowers at a time. In this respect the hybrid is similar to the pistil-parent, and the crowding of the broad flowers at the top of the spikes causes the hybrids to be much more showy than either of the parent types.
In the summer of 1895 I castrated some flowers of O. muricata, and pollinated them with O. biennis, surrounding the flowers with paper bags so as to exclude the visits of insects. I sowed the seeds in 1896 and the hybrids were biennial and flowered abundantly the next year and were artificially fertilized with their own pollen, but gave only a very small harvest.
O. muricata, with small corollas and narrow leaves, was introduced in the year 1789 by John Hunneman, and O. suaveolens, or sweet-scented primrose, a form very similar to the biennis, about the same time, in 1778, by John Fothergill.
Word Of The Day
Others Looking