BOTANY. 297 



confined to the uppermost or treeless region of the mountains. As the 

 continent grew by the slow upheaval of the land, and the islands gained 

 in height, and the climate around their base grew milder, the arctic plants 

 would retreat to higher and higher zones, and finally occupy an elevated 

 area, which probably had been at first, or in the glacial period, always 

 covered with perpetual snow. Meanwhile the newly-formed plains 

 around the base of the mountain, to which northern species of plants 

 could not spread, would be occupied by others migrating from the 

 south, and perhaps by many trees, shrubs, and plants then first created, 

 and remaining to this day peculiar to North America. Condensed from 

 LyelTs Secoiid Visit to the United States. 



PECULIARITIES OF FLOWERS. 



4 



WE find, in the Patent-Office Report for 1848\published about July, 

 1849), a translation of the results of some observations made by a Ger- 

 man botanist on the growth of certain plants. His experiments were 

 made with briony, pharcala, elder, and flax. " TJie growth of these 

 plants advanced uninterruptedly by day and night ; but, with the excep- 

 tion of the flax, the growth was more by day than by night. Further, 

 the observations made on the briony the first day showed, that, with the 

 increase of the heat of the sun, the growth of the outward portions of 

 the plants fell off, and also in disturbed and rainy weather. Flax grows 

 on an average more in the night than in the day, and more in troubled 

 weather than in sunshine, a proof that it requires for its success a 

 moist atmosphere." 



The same report also contains the results of the observations of 

 another botanist, on the coloring of flowers. The coloring of flowers 

 is intimately connected with the alternations of the seasons. " In con- 

 sidering the vegetables of our country (Germany), either in a mass 

 or in groups, we see invariably that the number of flowers increases 

 from December to July. White flowers are the most numerous 

 during the whole period of the year when plants are seen in blos- 

 som ; after these come the yellow, then the orange, the blue, the violet, 

 the green, and, lastly, the indigo flowers, which are the most un- 

 common. The law according to which the increase of flowering 

 takes place shows itself to be closely connected with the mean tem- 

 perature; but from time to time anomalies are exhibited, which the 

 change of temperature alone cannot explain ; such is the rapid de- 

 crease of the number of flowering plants from the end of July to 

 that of August. From the month of January, when all the flowers are 

 white, to the vernal equinox, the relative number of white flowers 

 rapidly decreases ; after that period the proportion of them increases 

 till the middle of May, and then insensibly diminishes till the time when 

 the frosts arrest all vegetation. If we set aside the very small 

 number of yellow flowers which appear in February and March, we see 

 that the proportion of flowers of that color increases from the be- 

 ginning of April to the end of June, then it remains stationary till 

 the middle of August, after which it increases again till the frosts 

 come. The proportional number of red flowers gradually diminishes 

 from February to the end of April, then recovers the ascending scale 



