526 Lead Trees 



the manufacture of perfumery; the pods are sometimes used in tanning and dyeing. 

 The plant is very ornamental and is used for hedges throughout the tropics. The 

 generic name commemorates Rev. C. H. Vachell, an EngUsh missionary and 

 botanical collector in China. 



VIII. LEAD TREES 



GENUS LEUC^NA BENTHAAI 



EUC^NA consists of about 15 species of evergreen, usually unarmed 

 trees or shrubs, natives of the warmer parts of America, with probably 

 one species in the islands of the Pacific Ocean; in addition to the arbo- 

 rescent species, one shrub, LeuccBjia retusa Bentham, occurs on our 

 southwestern border. 



The leaves are evenly bipinnate, with the leaflets large and in few pairs, or 

 small and in numerous pairs. The flowers are white and mostly perfect, in axillary 

 clusters or in terminal racemes of dense globose heads, the individual flowers being 

 sessile in the axils of small bracts; calj^x narrowly bell-shaped, 5-lobed; corolla of 

 5 distinct sharp or rounded petals; stamens 10, exserted, the filaments free; ovary 

 stalked, many-ovuled, the slender style terminated by a small stigma. The fruit 

 is a many-seeded legume; it is flat, broadly hnear, with thickened margins, the 

 transverse seeds obovate, flattened, usually brown and shining; endosperm hard, 

 thin. 



The name Leucaena is from the Greek and has reference to the white flowers; 

 L. glauca (Linnaeus) Bentham is the type species. 

 Our arborescent species are: 



Pinnae 10 to 20 pairs; twigs finely woolly. i. L. pulverulenta. 



Pinnae 6 to 10 pairs; twigs smooth. 



Leaves without glands between the pinnae; pod 7 to 15 cm. long. 2. L. glauca. 



Leaves with a large gland between each pair of pinnae; pod 15 to 20 



cm. long. 3. L. Greggii. 



I . MEXICAN LEAD TREE Leucaena pulverulenta (Schlechtendal) Bentham 



Acacia pulverulenta Schlechtendal 



This handsome Mexican tree enters our area in the rich bottom lands along 

 the lower Rio Grande in Texas, and is the largest and most stately tree of the 

 Mimosa family occurring in the United States, often reaching a height of 18 

 meters, with a trunk diameter of 5 dm. 



The trunk is straight and upright for several meters, and separates above into 

 widely spreading branches, forming an open round tree. The bark is 6 mm. 

 thick, light brown, breaking up into persistent scales; the twigs are somewhat 

 grooved and finely hairy at first, becoming round and pale brown. The leaves 



