STAIiTDLEY TREES AND SHRUBS OF MEXICO. 167 



Large tree, sometimes reaching a height of 50 meters and a trunk diameter 

 of 2 meters; bark light reddish brown, furrowed into narrow ridges; leaflets 

 ovate or oblong-lanceolate, 8 to 15 cm. long; fruit with a thin husk, the nut 

 rounded, reddish brown, thin-shelled ; wood hard, rather brittle and weak, 

 close-grained, light reddish brown, its specific gravity about 0.72. The follow- 

 ing names are reported from various parts of Mexico : " Nuez encarcelada," 

 " nuez chiquita," " nogal morado," " pacanero," " nogal de nuez chica," " nuez 

 lisa." 



The bark is said to have been-used in Mexico in the treatment of intermittent 

 fevers and for dyspepsia. The pecan is grown extensively in the southern 

 United States, and the nuts are an important article of commerce. The kernels 

 have a very agreeable flavor and are eaten alone or in candies and other sweet- 

 meats. Most of the cultivated forms have much larger nuts, with thinner 

 shells, than the wild trees. 



21 BETULACEAE. Birch Family. 



Shrubs or trees; leaves alternate, deciduous, dentate, the stipules usually 

 deciduous; flowers small, dioecious, in catkins. 

 Pistillate catkins conelike in fruit, the scales woody ; staminate flowers 2 or 3 



to each bract ; perianth none in the pistillate flowers 1. ALNUS. 



Pistillate catkins not conelike, the scales thin ; staminate flowers solitary above 

 the bract ; perianth present in the pistillate flowers. 



Fruit inclosed in a bladder-like closed sac 2. OSTRYA. 



Fruit merely subtended by a flat leaflike 3-lobed bract 3. CARPINUS. 



1. ALNUS Hill, Herb. Brit. 510. 1756. 



References: Fernald, Proc. Amer. Acad. 40: 24-28. 1904; Bartlett, Proc. 

 Amer. Acad. 44: 609-612. 1909. 



Numerous species of Alnus occur in the United States. The Mexican alders 

 have often been determined as A. acuminata H. B. K., and there are many ref- 

 erences in literature to the name, but that species, described from the Andes of 

 Peru, does not occur in Mexico. 



The bark of the alders is astringent and rich in tannin. It is used in Mexico 

 for tanning skins, giving them a red color, and it is employed also for dyeing 

 skins, blankets, etc., furnishing various colors according to the substances 

 combined with it. The Nueva Farmacopea Mexicana states that the leaves are 

 used as poultices for wounds, an infusion of the bark as a lotion in cutaneous 

 diseases, a decoction of the bark internally for scrofula and venereal diseases, 

 and a decoction of the fruit as an astringent lotion for inflammation of the 

 throat. 



The following vernacular names are reported, but it is impossible to deter- 

 mine the species to which they are applied: "Aile" or "ayle" (Jalisco, Mo- 

 relos, Oaxaca ; from the Nahuatl, "ailitl"); " abedul " (Veracruz, Oaxaca) ; 

 " olmo del pais" (Veracruz, Hidalgo, Ramirez); " palo de aguila " (Oaxaca, 

 Reko) ; " yaga-bizie " (Oaxaca, Zapotec, ReJco) ; "palo de lama" (Guatemala, 

 Pittier). The Spanish name " aliso" is used in New Mexico and in some parts 

 of Mexico. 



Leaves densely covered beneath with yellow wax glands 1. A. jorullensis. 



Leaves without glands beneath or the glands remote and inconspicuous. 



Mature strobiles 7 to 14 mm. long. Veins very coarse and prominent on the 

 lower surface of the leaves 2. A. firmifolia. 



