Page:Popular Science Monthly Volume 31.djvu/102

92 stems and leaves. The silver-maple plantlet is pulpy and already of a deep green when it falls from the tree, and probably is killed as soon as it becomes thoroughly dried. The seed runs many risks for the sake of being a sizable seedling the same season.

The box-elder (Negundo aceroides, Moench) belongs to a most closely related genus to the maples, and by some botanists it is placed with them in the genus Acer. The most striking difference is seen in the leaves, those of the box-elder being compound like the ash, hence one of the common names, "ash-leaved maple," while the leaves of the familiar maples are simple. In the box-elder the sexes are separated much more clearly than in the maples. One tree bears only staminate flowers while another has only pistillate blossoms, and therefore bears the fruit. To have good seeds it is necessary that at least two box-elder trees be in the same vicinity, and one of these must be male and the other female. This tree is the type of hardiness in the severe climate of the Northwest, but in this connection there are some points not easy of explanation. The box-elder of one section of the country may be identical in structure with specimens in a different climate, but widely different in hardiness. This brings to view again the law of adaptation as applied to the inherent ability to withstand the untoward circumstances that have surrounded the ancestry for long periods in the past. The same is true of many other species growing over wide areas of country. They may possibly retain the same botanical characteristics, but beyond all that the eye, with the aid of the best microscopes, can see, there is that which enables one plant to flourish when another will fail.

The 17th of April brought blossoms of Caltha palustris (L.), and Carex stricta (Lam.). The first is the marsh-marigold, or perhaps more familiarly known as the "cowslip." The genuine cowslip of the poets is a different plant, it being a primrose. The caltha is a pot-herb of no great merit, and does not possess that type of beauty which inspires the muse. The carex is the second sedge of the season. It doubtless has its place to fill in the scheme of creation.

April 18th introduced us to three species, the Populus monilifera (Ait.), or cottonwood; Antenaria plantaginifolia (Hook), the plantain-leaved everlasting; and Viola palmata, var. cucullata (Gray), the common blue violet. Spring has now fairly opened, for the violets have come. This day throws together in the list three very different plants. The poplar is one of the most wide-spread and hardiest of trees. It is the only kind of arboreal vegetation in many places along water-courses of the Northwest, in regions subject to severe climatic conditions. It can bear the heat and drought of summer and the extreme cold of winter when other forms succumb. It may be worthy of note that this hardy tree produces timber that is among the lightest on the list of woods in the United States. Its specific gravity is only .3886, or a little more than one third as heavy as water. We