oberholser: pycnonotine family of passeriformes 537 



The nondifferentiated foliage organ which bears cf and 9 

 reproductive organs, and continues to act as an assimilating 

 organ, being thus at the same time green and fertile, may be 

 considered to represent one of the possible forms of the ancestral 

 organs of grasses. 



From the data presented the following conclusions may be 

 drawn, which confirm the theories of Bower, MacDougal, and 

 Dufrenoy : 



Organs of grasses were at first all fertile but most of them 

 became sterile under the pressure of ecologic factors. The vege- 

 tative activity overshadowed the reproductive activity and 

 most organs become assimilating organs, viz., leaves. A few 

 remained fertile, and responded in diverse ways to their re- 

 productive specialization, attaining their greatest differentiation 

 in ordinary maize. 



BIBLIOGRAPHY 



Collins, G. N. Hybrids of Zea ramosa and Zeatunicata. Journ. Agr. Research, 



9: 383-395, pi. 13-21. 

 MacDougal, D. T. Aridity and evolution. Plant World, 12: 221. 

 Dufrenoy, J. Les donnees actuelles et les problhmes de la phytogeographie. 



(Literature cited.) Rev. G6n. Sci., 27: No. 10. 



ORNITHOLOGY. — Diagnosis of a new pycnonotine family of 

 Passeriformes. Harry C. Oberholser, Biological Survey. 



It requires but a superficial examination to discover that the 

 genus Irena is out of place among the Pycnonotidae. Apparently 

 it has been referred to that family because of its conspicuous 

 nuchal hairs, which are so characteristic a feature of the bulbuls; 

 and because of the lack of a better place. 



That this disposition has not been considered satisfactory is 

 evidenced by Dr. R. B. Sharpe's reference of Irena to the Dicru- 

 ridae, 1 which action was, however, soon, and properly, repudiated 

 by Dr. Sharpe himself. 2 As a matter of fact, the fairy bluebirds, 

 as the members of the genus Irena are called, with their metallic 



1 Cat. Birds Brit. Mus., 3: 265. 1877. 

 ! Cat. Birds Brit. Mus., 6: 174. 1881. 



