V. 2. THE ALDER. 217 



V. 2. THE ALDER. ALNUS. Tournefort. 



The alders are trees or tall shrubs, natives of the cooler re- 

 gions of the northern hemisphere, and, in a few instances, of 

 the mountains of tropical America and of Central Asia. They 

 have alternate, entire, deciduous leaves, and stalked buds, in 

 which the leaves, plaited and folded together, are protected by a 

 single scale. The aments are on branched stalks, the male, long, 

 cylindrical and pendulous ; the female, short, ovoid and erect. 

 The scales of the sterile aments are on stalks, with usually five 

 smaller, accessary scales, and three-flowered. The flower-cup 

 is four-parted and has four stamens. The scales of the fertile 

 anient are wedge-shaped, fleshy, and persistent ; the ovary com- 

 pressed, with two long stigmas. The strobile consists of woody 

 scales grown together. The seed-vessel or pericarp is com- 

 pressed, angular, woody, not winged, one-celled and one-seeded. 



The roots of the alders are large and strong, extending some- 

 what beneath the surface, with few radicles, and usually throw- 

 ing up, near the stem, many suckers. They are covered with 

 a thin, dark orange bark. 



The wood is soft, somewhat tenacious, and durable under 

 water. It is, almost universally, of a reddish or pale rose color. 

 The bark is thin and parts easily from the wood when the sap 

 is rising. The wood and the bark of the species found on the 

 Eastern continent are extensively used for dyeing and for tan- 

 ning, as the bark abounds in tannin. 



The alder usually occurs along streams, and performs an 

 important office in protecting their banks from the running 

 water. It may be readily propagated by layers, by cuttings, 

 by truncheons, or by seed. 



There are two species in Massachusetts : 



The Common Alder, remarkable for the glossy and often 

 glutinous surface of the leaves, and for their being larger to- 

 wards the end and rounded at the extremity ; and 



The Speckled, with large leaves, which are pretty thick, and 

 have their lower surface downy or bluish white, or rarely green. 

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