A STUDY OF RHUS GLABRA 1 87 



The eastern analogue, R. ithaccnsis, in Pennsylvania, does 

 not come into flower before the end of July or early August. 

 These segregates of R. glabra from the northwest, by their 

 almost vernal flowering, reassert for themselves a more distant 

 relationship to the eastern types than that which we should infer 

 from their visible characters alone. 



15. RHUS SANDBERGII, sp. nov. 



Rhus glabra var. sandbergii, Vasey & Holzinger in Herbarium 



Field Museum. 



Very dwarf, flowering and fruiting freely at 1.5-2 dm. high ; 

 branches of the season 4-5 cm. long, angular, rusty-tomentulose 

 and with also a few hirsute hairs, older branches glabrate : 

 leaves small, barely 1.5 dm. long, the slender rachis pubescent 

 on all sides; leaflets 11-13, sessile, oblong-lanceolate, 4-6 cm. 

 long, appressed-serrate, the serratures 15-17 on each margin, 

 apex subulate-acuminate, both faces nearly or quite glabrous, 

 the upper deep green, the lower glaucous : panicle very small, 

 seldom exceeding 5 cm. long, subpyramidal, its branches 

 densely and subtomentosely hirsute : drupelets of the ordinary 

 size and color. 



Said to grow in crevices of rocks, near the head of Lake 

 Superior at Thompson, Minnesota, where it was collected in 

 flower in July, and in fruit in August, 1891, by J. H. Sandberg, 

 who afterwards distributed it under numbers 401 and 921. His 

 locality for it is the only one known. I would indicate as the 

 type specimen the fruiting one on sheet 19898 of the National 

 Herbarium. Happily Mr. Sandberg, unlike most collectors of 

 Rhus specimens, gathered this in both flower and fruit. 



Prof. John M. Holzinger of the Normal School at Winona, 

 Minnesota, would have proposed this species as new, in his 

 paper published in the Minnesota Botanical Studies, part 8, in 

 1896, but was deterred by the opinion of some authority who 

 would have reduced R. typhina and R. glabra to one species, 

 with this as a connecting link between them. 



