160 JOURNAIv OF the; WASHINGTON ACADEMY OF SCIENCES VOL. 11, NO. 7 



Leaves 3-foliolate or often reduced to the terminal blade, glabrous or more 

 or less appressed-pubescent ; stipules subulate or linear, minutely pubescent; 

 petioles 1.5 cm. long in the simple leaves, 2.5 to 4 cm. in the compound leaves, 

 glabrous, broadly alate, the wings up to 7 mm. broad, acute or rounded below 

 the insertion of the leaflets; leaflets short-petiolulate, ovate-lanceolate, 

 rounded at the base, obtusely long-acuminate, the main primary veins (of 

 the terminal leaflets) 11 to 14, anastomosing along the margin, prominent 

 on both sides, the intermediate veins numerous and parallel; lateral leaflets 

 3.5 to 9 cm. long, 1.5 to 4 cm. broad; terminal and single leaflets 8 to 16 cm. 

 long, 3.5 to 6 cm. wide. 



Inflorescences 2- to 5-flowered, axillary or terminal, the rachis slender, 

 sparsely appressed-pubescent; pedicels subfiliform, 12 to 15 mm. long; buds 

 subglobose or broadly ovoid, glabrous, about 9 mm. long; calyx opening by 

 3 irregular segments, almost 10 mm. long; petal short-unguiculate, broadly 

 ovate, IG mm. long, 22 mm. broad; longer stamens S, the anthers elongate, 

 recurved; smaller stamens numerous and short; ovary long-stipitate (the 

 stipe 10 to 14 mm. long), 6- to 8-ovulate, glabrous, 6 to 8 mm. long, the style 

 straight, subulate, 5 to G mm. long. 



Legume not known. 



Type collected by von Tuerckheim at Cubiquiltz, Alta Verapaz, Guatemala, 

 in flower, May, 1901 (J. D. Smith, no. 7839). 



This plant, described by Captain John Donnell Smith as a variety of 

 Swartzia myrtifolia, differs from that species in several important particulars, 

 such as the disparity between the lateral and terminal leaflets, the con- 

 spicuousness of the main primary veins, the long acumen of the blades, the 

 broad wing of the petiole, the 3-laciniate calyx, the shape of the petal, the 

 8 long stamens (instead of 12 to 18), and the long-stipitate ovary. These 

 characters are sufficient to justify specific rank for this interesting member 

 of the Guatemalan flora. 



OCEANOGRAPHY. — Practical application of the electrical conduc- 

 tivity method of measuring sea water salinity.'^ A. L. Thuras. 

 (Communicated by S. W. Stratton, Bureau of Standards.) 

 Heretofore the only reliable method of measuring the total salt con- 

 tent of sea water has been by chemically titrating for the amount of 

 chlorine present. The relation of chlorine to the total salts being a 

 constant, a measure of the salinity is thereby obtained. Salinity is 

 defined as the number of grams of total salts in 1000 grams of sea 

 water. The titration method, being a laboratory method, requires 

 that the samples after collection be stored in suitable bottles until 

 they can be tested on shore. The disadvantages of such a method 

 are: the loss or breakage of samples, possible errors from evaporation 

 and handling, and the great undesirability of not knowing the physical 

 properties of the waters while they are being investigated. 



' Received January 31, 1921. 



