Rydberg : Studies on Rocky Mountain Flora 533 



Washington: 1889, G. R.' Vascy. 

 Oregon : /. 5. Nezvberry. 



Modoc Co., 1893, M. S. Baker; 1865, H. 



H. 



Colorado : Pagosa Peak, 1 899, C. F. Baker, 258 (?). (This 

 has smaller flowers, petals and sepals being only 6-8 mm. long.) 



ZYGADENUS Michx. 



Much confusion has existed in this genus. The species of 

 Colorado, Wyoming and Montana have been variously named Z. 

 Nuttallii, Z. veneuosiis and more rarely Z. panieulatus, but much 

 complaint has been made that they do not fit Watson's descrip- 

 tions. Some have complained that those descriptions have been 

 too narrow, others that there is no line to be drawn between Z. 

 veneuosiis and Z. panieulatus and that both those species come to- 

 near Z. Nuttallii. Dr. Watson's descriptions of Z, veneuosiis and 

 Z. paniculatus are unusually good and correct. He knew them 

 both from the field. The common Rocky Mountain plants belong 

 to neither. Z. veneuosiis does not grow east of Idaho and Z. pan- 

 iculatus not east of Utah, while Z. Nuttallii is a species of the plains 

 and I doubt that it is found at all in the Rocky Mountain States. 

 The Rocky Mountain species are distinguished as follows : 



Gland obcordate ; base of ovary inferior. 



Petals and sepals 7-8 mm. long, 7-13-nerved. Z. elegans. 



Petals and sepals 5-6 mm. long, 3-7-nerved. Z. Coloradcnsis. 



Gland obovate or semi-orbicular ; ovary wholly superior. 



Petals and sepals more or less clawed ; filaments adnate to the base of the claws. 

 Petals and sepals rounded or obtuse at the apex. 



Upper leaves without sheaths at the base ; both petals and sepals long- 

 clawed and sub-cordate at the base*; gland with a thick margin. 



Z. venenosus. 



All leaves with distinct sheaths ; petals long-clawed and sub-cordate at 



the base ; sepals short-clawed ; margin of the gland ill-defined. 

 Petals and sepals 4-5 mm. long ; petals ovate ; leaves 3-5 mm. wide. 



Z. gramineus. 



Petals and sepals 6-8 mm. long ; petals oblong ; leaves 5-9 mm. 



wide. Z. intermedins. 



Petals and sepals acute or acuminate at the apex ; all leaves with sheaths ; 



sepals cuneate at the base and short-clawed. 

 Leaves less than 5 mm. wide ; petals and sepals both cuneate at the base 

 and short-clawed. Z. (7<u/its. 



