308 GEOGRAPHICAL DISTRIBUTION OF PLANTS. 



an agreeable beverage in hot weather. S. argentea is a prairie 

 shrub common to the plains of the Missouri and Saskatchewan, 

 but which does not grow in the eastern districts. It is the 

 Mith-yu mina or blood-red berry of the Crees. 



THYMELEiE. — Direct palustris, leather-wood, is common in 

 the Northern States, and extends to the north side of Lake 

 Superior, disappeai'ing about the Lake of the Woods. 



Empetre^e. — Empetrum nigrum occurs on the alps of 

 New Hampshire and New York, and is found throughout the 

 whole extent of Rupert's Land up to the Arctic Sea, along 

 which it ranges to Kotzebue Sound, descending the western 

 coast to Sitka, and perhaps lower. It is absent only on the 

 prairies. In the more sandy tracts of the barren grounds it 

 covers the surface with its prostrate branches, that are loaded 

 with fruit in favourable seasons. The snow-geese feed and 

 fatten on the berries, which, after the fresh frosts, become very 

 juicy, and are highly refreshing to the weary and thirsty 

 traveller. 



ULMACEiE. — Ulmus americana, white elm, was found by 

 Lieut. Abert on the Pawnee Fork in latitude 38° 10' N., at an 

 elevation of 1,658 feet ; and Dr. Asa Gray informs me that it 

 descends to Texas. It is a majestic tree in the Northern States, 

 much prized for its rapid growth and the beauty of its form. 

 Its wood is in requisition there for the use of wheelwrights. 

 On the north banks of the Saskatchewan, in about latitude 

 54°, which is its polar limit, it grows only in rich alluvial 

 soil, and, being crowded among balsam poplars and other trees 

 which inhabit such places, does not exhibit its handsome outline 

 so as to strike the eye. Its timber there is often decayed at 

 heart, and, even when sound, is so porous that we found it to be 

 unfit for planking boats. It is probable that the U. fulva, 

 slippery or red elm, known by the corky and angled bark of its 

 branches, has an equal northerly range ; but we did not trace it, 

 though two kinds extend to the Saskatchewan, and we gathered 

 their flowers. It is perhaps an elm of which I heard, but did 

 not see in leaf, which inhabits wet places on the banks of 

 Rainy River, and produces a wood that is considered there to 



