1 84 ■ BOTANICAL GAZETTE [February 



Vegetation of a glacial plunge basin. — In certain rock basins of glacial 

 origin near Syracuse, New York, low soil and air temperatures prevail through- 

 out the year, the difference between the rim and bottom of the depressions 

 often amounting to 30° F. These temperature depressions have been shown 

 by Petry^9 to be the controlling factors in the development of plant associa- 

 tions characterized by distinctly northern species, such as Cornus canadensis, 

 Pyrola asarijolia, Coptis trifolia, and Ribes lacustre, whose local distribution 

 coincide exactly with areas of low soil and air temperature. — Geo. D. Fuller. 



Geotropism and phototropism. — Van Ameijoen-^" finds that neither geo- 

 perception nor photo-perception or reaction occurs in the seedlings of Avena 

 saliva or Sinapis alba in complete absence of oxygen. Contrary to Correns 

 and Kenkel, he finds that, on complete or partial withdrawal of oxygen, the 

 reaction of seedlings to a geotropic stimulus does not differ from their reaction 

 to a phototropic stimulus. — Wm. Crocker. 



Rusts of Costa Rica. — Arthur^' has studied the rusts of Costa Rica 

 based chiefly upon collections made by Holway, and this first presentation of 

 Costa Rican rusts includes 118 species, 22 of which are described as new, and 

 12 others are new to North America. The indications are that the rust flora 

 of Costa Rica will be found to be of exceptional richness and importance. — 

 J. M. C. 



Aquilegia. — Payson^^ has published a revision of the North American 

 species of Aquilegia. In addition to the keys, descriptions, and discussions, 

 there is an unusually full list of stations. He recognizes 25 species, 3 of which 

 are described as new, and also 9 subspecies or varieties, 2 of which are new. — 

 J. M. C. 



New African plants. — Moore,33 in connection with his studies of African 

 Compositae, has described a new genera {Emiliella) of the Senecionidae and 

 8 new species of Senecio. — J. M. C. 



^' Petry, Loren C, Studies of the vegetation of New York State. II. The vege- 

 tation of a glacial plunge basin and its relation to temperature. Bull. Torr. Bot. Club 

 45:203-210. 1918. 



30 Van Ameijden, U. P., Geotropism and phototropism in the absence of free 

 oxygen. Recueil Trav. Bot. Neerl. 14:149-218. pis. 15-19. fig. i. 1917. 



3' Arthur, J. C, Uredinales of Costa Rica based on collection by E. W. D. 

 HoLWAY. Mycologia 10: 111-154. 1918. 



3^ Payson, Edwin Blake, The North American species of Aquilegia. Contrib. 

 U.S. Nat. Herb. 20:133-157. pis. 8-14. 1918. 



33 Moore, Spencer LeM., Alabastra diversa. Part XXIX. Jour. Botany 56: 

 225-233. 1918. 



