safford: new genus rolliniopsis 197 



the temperature 1170° absolute. Actually this radiator is very 

 far from gray and has the temperature 1400° absolute. 



Using the valuable method of isochromatics and considering 

 the constant p of equation (4) the writers hope to present later 

 experimental data on the emissivity of carbon. It may be re- 

 marked that the intersections used directly give simply the tem- 

 perature at which a color match is obtained. It is also interest- 

 ing to note that a non-black material may show the energy dis- 

 tribution of a gray body and still not be gray. That is, it is 

 theoretically possible to obtain a color match against a black 

 body with certain materials which have an emissivity coefficient 

 varying greatly with the wave length. It is theoretically pos- 

 sible to have two radiators at different temperatures, one gray 

 and the other far from gray, giving an exact color match, and 

 an exact intensity match at every wave length. 



BOTANY. — Rolliniopsis, a new genus of Annonaceae from Bra- 

 zil. W. E. Safford, Bureau of Plant Industry. 1 



Among the plants collected by Messrs. Dorsett, Shamel, and 

 Popenoe while on their mission of agricultural exploration in 

 Brazil, in 1914, there is one of peculiar interest, belonging to the 

 Annonaceae, with 3-winged flowers resembling those of a Rol- 

 linia but with clusters of small, one-seeded, orange-colored fruits 

 very much like those of a Guatteria or Aberemoa. A photo- 

 graph of the flower and fruit was taken in the field, and plants 

 propagated from the seeds were distributed by the Office of 

 Foreign Seed and Plant Introduction, Bureau of Plant Industry, 

 bearing the label " Guatteria sp., S. P. I. No. 37902." 



A second species having the same botanical features was 

 brought back from Brazil more recently by Dr. J. N. Rose and 

 Air. P. G. Russell, who collected it in the state of Bahia, in the 

 summer of 1915, while carrying on botanical exploration under 

 the auspices of the Carnegie Institution of Washington. 



For these and two allied plants hitherto assigned to the genus 

 Rollinia (R. parmflora St. Hil. and R. leptopetala R. E. Fries) must 

 be created a new genus, for which I here propose the name 

 Rolliniopsis. 



1 Published with the permission of the Secretary of Agriculture. 



