304 GEOL-OGICAL SURVEY OF CANADA. 



" Biennial, rarely somewhat glaucous ; stems erect, one or several, 

 usually simple, 1 to 3 feet high ; lower leaves oblanceolate, usually 

 dentate, finely stellate-pubescent or sometimes glabrous, the cauline 

 oblong to linear- lanceolate, auriculate ; flowers white or pinkish ; pods 

 more or less spreading or sub-erect, a line broad or less, straight or 

 slightly curved, usually more or less attenuate above and beaked; seeds 

 small, narrowly oblong, winged." This includes all A. Drummmdii 

 and var. hrachycarpa from the Atlantic to the Eocky Mountains. 



(138.) A. Drummondii, Gray. 



Only the Eocky Mountains and westward are included in the range 

 of this species. Fine specimens were collected at Kamloops, Spence's 

 Bridge and Lytton, B.C., in the summer of 1889. (Macoun.) 



(30*75.) A. Columbiana. 



Eesembing A. arcuata in the shape of the pods, but differing very 

 much in general appearance. The pods are longer and are exactly 

 sickle-shaped, and the pedicel is shorter ; flowers white, calyx almost 

 smooth, but occasionally with a few branching hairs which are more 

 numerous on the leaves and stem, especially towards the base ; leaves 

 at the foot of the stem slightly toothed and tapering into a petiole, 

 those of the stem sessile and often clasping. It may be designated 

 a winter annual as its seeds are ripe early in May. Quite common on 

 the lower slopes of the mountains bordering the Thompson and Eraser 

 rivers from Spence's Bridge to Yale, B.C. First detected May 19, 1875. 

 {Macoun.) 



(2101.) A. canescens, Nutt. 



On mountain slopes in the dry I'egion of British Columbia, Cherry 

 Bluff, near Kamloops, and throughout the Nicola Valley. (Dawson.) 

 Along the mountain slopes at Yale, Lytton, Spence's Bridge, and 

 Kamloops, B.C. (Macoun.) 



46. SISYMBRIUM. 



(157.) S. humile, C. A. Meyer; Gray, Man., ed. VI., 11. (1890.) 

 Arabis petrsea, Macoun, Cat., I., 42, & III., 486. 



Since Parts I. & III. of my catalogue were published. Dr. Watson has 

 carefully looked into the various specimens of A. petrcea sent from 

 Canada, and has referred most of them as above. It follows therefore 

 that almost all references to A. petrcea in Parts I. & III. must be con- 

 sidered cancelled. See A. humifusa. 



