et in species novas atque affines divisa. 315 
historically speaking, that enters into Linnaeus’ aggregate; and had the 
latter described his Rhus species as carefully as Bauhin had described 
his a hundred and thirty years before him, the task of the twentieth | 
century botanist at this juncture would have been much less difficult. 
9. Rhus arbuscula E. L. Greene, l. c., p. 184. 
Shrub low, tree-like in form though commonly less than 1 m high; 
branches of the season glabrous, glaucous, obscurely angled, not very 
stout, but foliage large and ample; largest leaves 3 dm long, of 11 to 13 
rather remote leaflets, these lance-oblong, 7 to 9 cm long, often sub- 
falcate, notably inequilateral at base, never quite sessile, the petiolule 
definite though very short, upper face of leaflets light or deep-green, . 
the lower very glaucous; serratures moderately salient, 10 to 15 on each 
margin, the apex abruptly and sharpiy acuminate; panicie pyramidal, 
very small for the foliage, usually but 7 to 9 em long; drupelets of the 
smallest. 
Near Culver, Marshall County, Indiana; collected August 18, 1906, 
- by Mr. H. Walton Clark. 
The type locality, and thus far the only known station, is a barren 
hill above the eastern shore of Lost Lake, near Culver, Indiana. The 
specimens at hand are two, both of them excellent, but evidently not 
from the same bush, and, as I suspect, from somewhat different ex- 
posures. One of them has a maturer foliage beginning to redden for the 
autumn; and the branch, as well as the rachis of the leaves in this all 
show much bloom. This I designate as the type specimen. The other 
differs only in having foliage of a clear and vivid green, and the stem 
shows but little bloom. Both specimens have been presented to, and will 
be preserved, in the U. S. National Herbarium. 
10. Rhus petiolata E. L. Greene, l. c., p. 185. 
Branches not stout, glabrous, glaucous, striate, roughened also by 
small and very protuberant lenticels; leaves ample, not long, though 
long-petioled; leaflets about 13, large, 8—10 cm long, oblong-lanceolate 
and often subfalcate, distinctly petiolulate, the base obviously inequi- 
lateral, apex sharply acuminate, the sides sharply but unevenly serrate, 
the serratures 13 to 15, upper face of leaflets of a rich deep green, the 
lower very glaucous; panicle small for the foliage, pyramidal, 10 cm 
high, compact, the branches thinly and rather stiffly hirtellous; drupelets 
rather large. 
Prairie region of the interior of Minnesota, the type from near 
Spicer, Minn., August, 1892, W. D. Frost, Herb. Field Mus. Well marked 
by the large definitely petiolulate leaflets. 
11. Rhus valida E. L. Greene, |. c., p. 185. 
Branches very stout and robust, upright, at the end of the first 
season no longer glaucous but light brown, between cinnamon and 
chestnut-color, striate, copiously lenticellate; leaves not large in pro- 
portion, less than 3 dm long; leaflets about 15, approximate, short- 
