184 GREENE 



fancy almost or quite to the rank of a probability is the at least 

 highly interesting coincidence that my type specimens of R. 

 ludoviciana bear the only leaves and leaflets known to me that 

 answer to Bauhin's description of those of Burser's specimen. 

 He gave the number of the leaflets, their form and dimensions, 

 the serrated character of their margin, and the narrowly atten- 

 uate apex, not omitting mention of the darker green upper and 

 paler lower faces of the leaflets. 



This, as I have said before under R. glabra, is the earliest 

 element, historically speaking, that enters into Linnaeus' aggre- 

 gate ; 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. 



11. RHUS ARBUSCULA, sp. nov. 



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 subfalcate, notably inequi- 

 lateral 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 sharply acuminate : panicle 

 pyramidal, very small for the foliage, usually but 7 to 9 cm. 

 long ; drupelets of the smallest. 



Near Culver, Marshall County, Indiana ; collected August 18, 

 1906, by Mr. H. Walton Clark, of the United States Bureau of 

 Fisheries. 



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 excel- 

 lent, but evidently not from the same bush, and, as I suspect, 

 from somewhat different exposures. 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. 



