Sourwood 



757 



specific gravity is about 0.75. This tree deserves a place in parks and lawns of 

 warm temperate regions on account of its peculiar foliage and profusion of small 

 flowers. 



Xolisma, of which this species is the type, contains about 10 species, occur- 

 ring in North and Central America and the West Indies. The name is Greek 

 and is supposed to have been intended for Cholisma, meaning defective, in refer- 

 ence to the smaller corolla and other differences from closely related genera. 



V. SOURWOOD 



GENUS OXYDENDRUM de CANDOLLE 

 Oxydendrum arboreum (Linnaeus) de CandoUe 

 Andromeda arborea Linnaeus 



HIS tree is the only species of its genus, and occurs in woodlands from 

 southern Pennsylvania and Mar}'land to Florida, westward to Indiana, 

 Tennessee, and Louisiana. It attains a maximum height of about 

 20 meters, with a trunk diameter of about 5 dm. It is locally known 

 as Sorrel tree. Elk-tree, Sour gum, Arrowwood, Titi, and Lily-of-the- Valley tree. 



The smooth bark is thick, reddish gray 

 and furrowed. The young twigs are smooth, 

 light green, becoming orange to browTi. The 

 alternate deciduous leaves are shining, 10 

 to 15 cm. long, oblong to oval-lanceolate, 

 sharply and' finely toothed, rather long- 

 pointed, smooth and bright green on both 

 sides, narrowed at the base; the leaf-stalks 

 xsLvy from i to 2 cm. in length. The numer- 

 ous white flowers are in nodding, clustered 

 racemes at the ends of branches, and open in 

 June or July; their short, ashy-hair)' stalks 

 bear 2 minute bractlets at about the mid- 

 dle; there are 5 short sepals, which remain 

 attached to the base of the ashy-hair}^ fruit; 

 the corolla is ovoid-cylindric, 6 or 7 mm. 

 long, and 5-toothed; there are 10 stamens Fig. 692. - Sounvood. 



about as long as the corolla, the filaments wider than the linear anthers, which 

 open by long chinks to release the pollen; the oysltx is 5-celled and is surmounted 

 by a slender columnar style, which is tipped by the minute stigma. The fruits, 

 borne on curved stalks, are ovoid-pyramidal, rather woody, and 4 to 6 mm. long, 

 5-angled, tipped by the style, and split into 5 valves when mature. 



The wood is hard and reddish brown. The tree is valuable for ornamental 

 planting as far north as Massachusetts, often flowering when less than 2 meters 



