2a. Section Alleghenienses L.H. Bailey (highbush blackberry)

Canes erect to high-arching the first year, generally more clearly arched the second year; clonal by root-suckering, but rarely observed to tip-root. Prickles broad-based, straight or somewhat downward-curved. Primocane leaves with (3)5 leaflets. Sepals tapered to long-tapered at the tips, the outer surface often bearing stalked glands. Petals white. Some part of the plant always bearing stalked glands, most often the flower stalks. About 6 species, eastern U.S. and adjacent Canada.

Alice et al. (in press) treat members of this section under a broadly circumscribed R. allegheniensis. On the other hand, Steyermark (1963) divided Missouri’s representatives of sect. Alleghenienses into two taxa: R. allegheniensis, with narrow, cylindric inflorescences, and R. orarius Blanch., with wider, upward flaring ones. Yet, W. H. Blanchard’s (1906) description of R. orarius is so vague that this species could be placed in three different sections, and he designated no holotype. L. H. Bailey (1944) treated it in sect. Alleghenienses, but also stated that it might as easily be included in either sect. Arguti or sect. Canadenses L.H. Bailey. He did not designate a lectotype. Davis et al. (1969) discussed it in their revision of sect. Arguti. All of these authors, along with Fernald (1921), restricted R. orarius to Maine, Massachusetts, and Nova Scotia. Specimens that would key out as R. orarius in Steyermark (1963) are treated herein as R. alumnus and R. rosa, two polyploid taxa.