MEMOIRS FEOM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY 193 



Illustrations: Hook. Fl. Bor. Am. 1: pi. 63; Lindl. Bot. Eeg. 16: pi. 1379; Britt. 

 & Brown, 111. Fl. 2 : /. 1913. Plate 102, f. 1, 2; dissection of flower, /. 3; pistil, /. A; 

 stamen, /. 5 ; fruiting hypanthium and calyx, /. 6. 



Stem stout and erect, 3-10 dm. high, striate, generally densely glandular or viscid, 

 hirsute with spreading hairs, generally simple below, branched above, with very short 

 nearly upright branches. Lower stipules ovate-lanceolate, submembranous and sub- 

 entire, the upper broadly ovate and coarsely dentate or entire. Basal leaves many, with 

 petioles 5-20 cm. long, pinnate ; leaflets 3-5 pairs, strongly veined, densely pubescent on 

 both sides with appressed hairs, or those on the veins spreading. Upper three leaflets 

 larger than the others, 2-10 cm. long, generally 4-5 cm., doubly serrate, the odd one gener- 

 ally rhomboid, the others usually obliquely ovate ; the lower pairs gradually diminishing 

 downward. Stem leaves similar but smaller, with short petioles and fewer leaflets. Flowers 

 in a crowded dense, strict cyme, 12-18 mm. in diameter. Hypanthium glandular viscid, 

 in fruit enlarged. Bractlets lanceolate, much smaller than the oblong-ovate acute or mu- 

 cronate sepals. Petals broadly obovate or nearly orbicular, white or ochroleucous, in dry- 

 ing turning yellow, a little longer than the sepals. Stamens 25-30, most commonly 30 ; 

 anthers flat, slightly cordate at the base. Pistils numerous ; achenes smooth ; style basal 

 or nearly so, fusiform. 



This is the only eastern species of the genus, extending from New Brunswick to the 

 District of Columbia, westward to the foothills of the Rocky Mountains, from Colorado, 

 as far north as Fort Simpson, on the Mackenzie River. It differs from the others by its 

 pubescence, which is coarser, densely hirsute and glandular, and by its dense and strict 

 cyme. Dr. Watson observes that in the Rocky Mountain region there is found a form 

 of P. arguta with bright yellow flowers. This is probably a mistake, and the specimens 

 referred to belong to D. glutinosa. 



The variety ferruginea described by Lehmann I can but regard as a large form of the 



species. The plant very commonly takes on a brownish or ferruginous hue in age. The 



Potentilla ferruginea of Paxton's Magazine,^ cited by Lehmann, has nothing to do with 



this speces; it is a true Potentilla, a hybrid of the purple-flowered P. atrosanguinea with 



the yellow P. pedata. 



2. Drymocallis convallaria. 



Potentilla convallaria Rydberg, Bull. Torr. Bot. Club, 24 : 249. 1897. 

 Illustrations : Bull. Torr. Bot. Club, 24 : pi. 306. Plate I04. 

 Stem tall, erect, 4-10 dm. high, long-villous but not very densely so, glandular or 

 viscid, especially above, branched above with long erect branches. Stipules ovate or 



1 5: 233. 1838. 



