Minnesota Plant Life. 



249 



niture, being utilized as an imitation of mahogany. For this 

 purpose, too, the wood of the black birch is even more excel- 

 lent. This species, however, occurs but sparingly in Minne- 

 sota and is found only in the extreme northern part of the state. 

 It is from this species that birch-oil and the extract used in 

 flavoring birch beer are manufactured. Of the shrubby birches 

 the most abundant is the low birch which is found in peat-bogs 

 pretty commonly through- 

 out the state. 



Alders. Related to the 

 birches are the alders, of 

 which two varieties occur in 

 Minnesota, the green alder 

 and the black alder. These 

 may be distinguished from 

 the low birch, which they 

 resemble, by their more en- 

 tire leaves and short, com- 

 pact, cone-like clusters of 

 nutlets. The low birch has 

 rather more elongated 

 spikes of pistillate flowers, 

 two and a half times as long 

 as they are thick, while the 

 alder spikes are about half - 

 as long again as thick. The 

 alders are to be looked for 



in tamarack SWampS Or in FIG. 115. An oak twig with leaves and both sort-* 



j i of flowers. The one with three prongs is the 



Open WOOdS, Where, eSpe- pistillate flower; the other, with five stamens, 



daily in damp places, they is the rtaminate. The *aminate flowers grow 



3 in drooping clusters. After Atkinson. 



may form an underbrush. 



Oaks. There are in Minnesota sev^n species of oaks, the 

 red, the scarlet, the black, the white, the bur, the chestnut and 

 the scrub chestnut-oak. Oaks form a large genus of plants, 

 comprising some three hundred species and well distributed 

 throughout the temperate regions of the northern hemisphere 

 and at high altitudes in the tropics. There are some 

 species in North America. They are distinguished by the fru: 

 known as the acorn, consisting of a nut or one-seeded fruit. 



