230 



ovalada, un poco comprimida y carinada, con un diente recio 

 en un costado, y termina el otro una punta gruesa formada por 

 el estilo." 



The fruit of the North American plant does not show the 



Fig. I. Achenes of (a) Myosuriis apetalus and (b) M. arislatus. 



prominent tooth which characterizes the Chilean plant. This 

 difference has probably been overlooked by all who have referred 

 our species to the latter, a difference which, if constant, should 

 suffice to keep as distinct two forms already separated geograph- 

 ically by thousands of miles. 



The accompanying figures and key will serve to elucidate the 

 difference between the two species: Figure a is an exact copy of 

 the illustration by Gay* representing the achene of M. apetalus. 



Achene with prominent keel along the ventral margin, and with a 



conspicuous tooth-like projection near the middle of the keel. M. apetalus. 



Achene not prominently keeled, nor toothed. M. aristatus. 



Washington, D. C. 



SHORTER NOTES 



A New Form of CortU^lorrhiza. — On June 21, 19 16, I found 

 a clump of Corallorrhiza near Long's Peak Inn, Larimer Co., 

 Colorado, growing under aspen trees with Arnica cordifolia and 



* Historia fiscia y politica de Chile (Bot.), i : 31, pi. i, f. i (a-d), 1845. 



