standley: north American amaranthaceae 391 



and dissolved in hydrochloric acid, and the analysis was conducted 

 by the ordinary methods. Magnesia was not determined owing 

 to lack of material. The optical study of the insoluble portion 

 showed that the augite and titanite crystals had not been at- 

 tacked, so no correction is needed for impurities introduced from 

 this source. The results are as follows, an average of four out 

 of many fairly accordant analyses of Vesuvian nephelite being 

 given for comparison. 



A B C Ba 



Si02 40.27 43.34 42.93 0.722 0.722 2.26 



AI2O3 31.05 33.45 33.84 0.320 0,320 1.00 



FesOs 2.42 2.60 0.40 0.016 



MgO - - 0.15 



CaO 0.81 0.87 2.08 O.OlSl 



NasO 15.11 16.28 15.39 0. 263 [ 0.315 0.99 



K2O 3.22 3.46 5.08 0.037] 



H2O - - 0.18 



Insol 7.51 0.12 



100.39 99.99 100.17 



A. Nephelite. Monte Ferru, Sardinia. H. S. Washington analyst. 



B. Same, calculated free from insoluble. 



C. Nephelite. Monte Somma. J. Morozewicz, analyst. Bull. Acad. Sci.' 

 Crac. 8:979-983. 1907. 



Ba. Molecular ratios of B. 



BOTANY. — The North American tribes and genera of Amarantha- 

 ceae.^ Paul C. Standley, National Museum. 



The North American representatives of the family Ama- 

 ranthaceae have received little attention from Amerfcan botanists 

 in either early or recent years. This may have resulted from 

 the unattractive aspect of most of the plants composing the 

 group, but more probably from the circumstance that their 

 generic and specific characters are based chiefly upon very 

 minute floral structures. Because of the small size and often 

 complicated structure of their flowers the plants have, indeed, 

 been considered a ''difficult" group, when, as a matter of fact, 

 they are remarkably easy of recognition, and of disposition, 

 provided that generic limits are agreed upon. The species, as 

 a rule, are sharply differentiated. Confusion as to generic limits 



' Published by permission of the Secretary of the Smithsonian Institution. 



