128 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
A plant has long appeared in the Pharmacopoeias under the name of Rhus Toxicoden- 
dron. Botanists are not agreed whether this plant is a separate species from the one under 
consideration, or whether they are varieties of the same. Linnaeus made them different 
with the distinction of the leaves being naked and entire in Rhus radicans, while they are 
pubescent and angular in Rhus Toxicodendron. Michaux and Pursh whose opportunities 
of observation have been more extensive, consider the two as mere local varieties; while 
Elliott and Nuttall still hold them to be distinct species. Among the plants which grow 
abundantly around Boston, I have frequently observed individual shoots from the same 
stock having the characters of both varieties. I have also observed that young plants of 
Rhus radicans frequently do not put out rooting fibers until they are several years old and 
that they seem, in this respect, to be considerably influenced by the contiguity of supporting 
objects. 
The attitude %aken by Bigelow has been sustained by later botanists, 
among them Torrey and Gray (58) who consider R. radicans a variety of 
R. Toxicodendron. 
Rhus diversiloha was first discovered by Douglas at Fort Vancouver on 
the Columbia river about 1830. Upon examination of this specimen W. J. 
Hooker (26), although he considered it "nearly allied, as this assuredly is, 
to the two preceding species [R. Toxicondendron and R. radicans],'' neverthe- 
less "ventured to consider it distinct." He therefore gave it botanical 
significance as Rhus lohata. To support his conclusion he advances the 
following reasons : 
It's general habit is very different, having erect straight stems and numerous small 
leafy branches. The leaflets besides being deeply lobed with acute sinuses are truly ovate, 
very obtuse, and greatly smaller than in any state of R. Toxicodendron, or R. radicans, which 
I have seen; the panicles, too, are exceedingly numerous. 
A free translation of Hooker's Latin description of the plant is as follows : 
Bush erect, 3-4 feet, branches round with the youngest ones pubescent, 
branches numerous, short, spreading, leafy. Leaves long-petiolate, trifoliate, 
with little leaves ovate, 1-2 inches long, very obtuse, membranaceous, at 
the base sometimes acute, sometimes rotund or truncate, beneath especially 
pubescent, deeply and variously lobate, terminate one sub-long-petiolate, 
each side sub-equally lobate with lobes generally less than 3, with little 
lateral leaves at the exterior margin more deeply lobate. Flowers (male) 
yellow, in loose racemes, shorter than leaf, longer than petiole. Bracts at 
the base of the branches oblong, ciliate. Calyx deeply parted with oblong 
lappets. Petals 5, much longer than the lappets of the calyx, obovate into 
a tongue evidently with attenuated base, at the back veined. Stamens 5, 
erect, little shorter than petals. Filaments subulate. Anthers 5, somewhat 
more greatly ovate, pale yellow, with cells sub-opposite. Style small, 
extending from the center of a platter-shaped disc situated in the bottom of 
the calyx, margin of the disc elevated, curled. 
The next known discovery of R. lohata was that of Capt. Beechy (Hooker 
and Arnott, 27) at San Francisco and Monterey Bay about 1832. These 
specimens differed in no respect from the more northern ones discovered by 
Mr. Douglas. 
The observations of Nuttall (Torrey and Gray, 58) furthered the 
botanical knowledge of the plant. He noticed that 
