STUDIBS OF THAIICTRACBAB — II. 89 



Studies of Thalictraceae. — II. 



Soon after having determined that the tall white-stemmed 

 meadow-rue of the Potomac Valley was really nameless, I had 

 fixed upon the name T. praealtum for it, in my mind ; yet, 

 when coming later to the actual writing of its description, I 

 seem to have allowed another word of the same import to 

 usurp its place in the manuscript, and in the proof-reading it 

 was as inadvertently allowed to stand. I now therefore write 

 ThalicTrum praealtum, to take the place of the synony- 

 mous T. altissimum of page 58 preceding. 



The present paper, it will be seen, has to do with small 

 montane species of a very marked and peculiar group. 



Thalictrum cheilanthoides. Plants tufted, the scapes 

 slender, 3 to 5 inches high, often with a leaf of 1 to 3 leaflets 

 in the middle ; basal leaves J^ to 1 inch long on slender 

 petioles of equal length; leaflets 9 to 11, of a vivid green 

 above, glaucous beneath, in outline from subreniform to 

 cuiieate-obovate, rather deeply broadly and obtusely lobed, 

 the lobes alone with abruptly elevated veins as to the green 

 upper face, the whole of the glaucous lower face traversed by 

 veins much less elevated : pedicels of the flowers almost fili- 

 form, long and ascending, though with a slight downward 

 curvature : sepals oblong, obtuse, greenish : filaments linear- 

 oblong, prominently and rather sharply mucronate, the mucro 

 more or less distinctly curved and hook-like : fruit not seen. 



Summit of Bald Peak not far from Santa Fe, New Mexico, 

 at 12,000 feet, collected by Paul C. Standley, 11 July, 1908 ; 

 his n. 4324 as in various herbaria. Distinct from all other 

 western montane allies of T. alpinum by the green coloring 

 of the upper face of its foliage, in which respect it evinces an 

 affinity for real British T. alpinum / but it has not the shin- 

 ing green that is so characteristic of genuine T. alpinum, as 

 well as of some of its American varieties or subspecies of our 



IvBAFI,BTS, Vol. II, pp. 89-104. 9 July, 1910. 



