May 19, 1921 pittier: bursera 229 



isophane and altitude index; and the phenological index; each modi- 

 fied by topographic, geologic, soil, and other features so as to define 

 local subdivisions, even down to specific places only a few rods or 

 feet in extent which may represent an element or feature of distinction. 

 When we learn to recognize and properly interpret these various 

 guides to the major and minor features of a bioclimatic zone, it will 

 be an easy matter to determine not only what zone is represented by 

 a given region and section of the country, but what section or minor 

 element of a zone is represented by a given place on a given farm. 

 Then we will realize all and far more than Dr. Merriam and others 

 have claimed for the life zones as guides to the development of human 

 welfare in food, health, and prosperity. 



BOTANY. — Two new species c/ Bursera.^ Henry Pittier. 



The two new species of Bursera here described have been found by 

 the writer in the course of study of the Central American material of 

 this genus in the United States National Herbarium. 



Bursera panamensis Pittier, sp. nov. 

 Low tree or shrub; branchlets short, thick, glabrous, grayish; leaves pin- 

 nate, small, the rachis pubescent, 1 to 4 cm. long, narrowly winged be- 

 tween the two lower pairs of leaflets, more broadly so between the upper pair; 

 leaflets 5 to 9, subcoriaceous, sessile or almost so, ovate to ovate-lanceolate, 

 the lateral ones rounded, the terminal one acute at base and apex, serrate 

 and slightly revolute on margin, sparsely hairy above, grayish tomentose 

 beneath; flowers unknown; fruiting racemes pubescent, 2 to 3 cm. long, 

 sparsely branched; drupes pedicelled, glabrous, subglobose, 6 mm. long, the 

 pedicels 5 mm. long, bearing at the apex the persistent calyx. 



Type in the U. S. National Herbarium, no. 715171, collected near the salt 

 works at Aguadulce, Province of Code, Panama, December 6, 1911, by 

 H. Pittier (no. 4993). 



This species belongs to the group of Bursera tontentosa (Jacq.) Tr. & PI., 

 with pedicellate flowers and membranous, serrate or crenate leaflets, these 

 more or less hairy on both faces. It is called "almacigo de^cruz" by the 

 natives of Aguadulce. The fluid oleo-resin which distils from the trunk and 

 the decoction of the young leaves are popular medicines, the first being used 

 .as a calmant and the latter as a diuretic. 



Bursera verapacencis Pittier, sp. nov. 

 Small tree or shrub; branchlets short, at first densely hairy; leaves clus- 

 tered at the ends of the branchlets, alternate, bipinnate at the base, pilosulous 

 above, densely brownish-hairy beneath, up to 5 cm. long and 4 cm. broad, 

 the rachis very slender and narrowly winged; pinnae and leaflets 17 to 23, 

 the former 6 to 10, each with 7 to 11 pairs of leaflets, these sessile, ovate or 

 *oblong, entire, rounded at the base, subacute at the apex, 2 to 8 mm. long, 



' Received February 11, 1921. 



