204 



less clearly related to the modern Selaginella, bat they need not 

 be further considered in the present connection. 



SHORTER NOTES 



Is Carduus undulatus Nutt, Found in Colorado? 

 When, a numbec of years ago, I began collecting botanical speci- 

 mens in Colorado, and later began collecting thistles, I supposed 

 I would find Carduus undulatus Nutt. As time went by and I 

 did considerable collecting, and became somewhat acquainted 

 with the many forms of Cardims I began to doubt if It is to be 

 found here. 



The habitat of Carduus undulatus according to Nuttall is, "On 

 the calcareous islands of Lake Huron and on the plains of Upper 

 Louisiana"; and it was said to be i to 2 feet high. A part of 

 Dr. Gray's description is, "principal bracts of the involucre . . . 

 comparatively small and narrow, tipped with an evident spread- 

 ing prickle." I have specimens of a Carduus collected by Dr. J. 

 Lunell at Butte, Benson Co., North Dakota, which answer Dr. 

 Gray's description of Carduus undulatus Nutt., and I am sup- 

 posing they represent the true C. undulatus. 



On the eastern side of the mountains in Colorado there are 

 three species, some of which have been taken for C. undulatus. 

 One of these is now C. Plattensis Rydb.; and since it has been 

 described and its specific characters pointed out, it is readily 

 recognized and considered to be distinct from C. undulatus. 

 Anothe*- species which I suppose has been taken for the latter 

 is C. megacephalus (Gray) Smyth. This is somewhat variable, 

 especially in size, but it is characterized by the broader involucral 

 bracts, and stouter spines, and I think may be readily recognized. 

 The third member of the group is C. Floodmani Rydb. This is 

 quite common on the plains, and in some respects answers better 

 the description of C. undtdatus than do the other two, since the 

 involucral bracts may be said to be "comparatively narrow, and 

 tipped with an evident spreading prickle." 



Those on the western slope belonging to the group of C. un- 

 dulatus, according to Dr. Rydberg's Flora of Colorado, are: C. 

 Traceyi Rydb., C. ohlanceolatus Rydb,, C. canescens Nutt., and 



