United States or Democratic Republic of the Congo ? Vote for the TOP Country of the Week !
It must be borne in mind that an ordinary systematic species may include many dozens of elementary forms, each of which remains constant and unchanged in successive generations, even if cultivated in the same garden and under similar external conditions. Leaving the violets, we may take the vernal whitlow-grass or Draba verna for a second illustration.
The geographic distribution of these elementary species of the whitlow-grass is quite distinct from that of the violets. Here predominant species are limited to restricted localities. Most of them occupy one or more departments of France, and in Holland two of them are spread over several provinces.
And it was a proof of her confidence in him that she wished to take his advice about her costume. Then he turned to other matters; for, as the slow weeks went by, one eagerly disposed to look for the signs of the coming spring might occasionally detect a new freshness in the morning air, or even find a little bit of the whitlow-grass in flower among the moss of an old wall.
Alpina. Alpine Whitlow-grass. One female and six males. Four of these males stand above the other two; whence the name of the class "four powers." I have observed in several plants of this class, that the two lower males arise, in a few-days after the opening of the flower, to the same height as the other four, not being mature as soon as the higher ones. See note on Gloriosa.
Subsequent to the period which has produced the numerous elementary species of the whitlow-grass came a period of widespread distribution. The process must have been wholly comparable with that of acclimatization. Some species must have been more adapted to northern climates, others to the soils of western or eastern regions and so on.
Word Of The Day