SEGREGATES OF RHUS. 123 
A Lower Californian species, collected by Purpus and dis- 
tributed for a variety of Z. diversiloba, to which it is in no wise 
related. It may represent a Mexican type of the genus, and one 
farther removed from the Californian type than is even Atlantic 
slope Toxicodendron. 
T. PHASEOLOIDES. Akin to the last, but at least sometimes 
rooting at the nodes and climbing, the internodes not elongated 
but leaves and flower-clusters approximate: leaflets rhombic- 
lanceolate, abruptly acuminate, entire or coarsely dentate: pani- 
cles short, ascending: fruits larger, spherical, not depressed. 
Turucahi, Sonora, Mexico, C. V. Hartman, n. 102, of the 
1894, collection, as in U. S. Herb. No. 589 of the same collec- 
tion, from St. Diego, 1891, is probably the same. 
T. LAETEVIRENS. Stems long and slender, not upright, more 
or less geniculate, rooting at some nodes, the bark light gray, 
puberulent: foliage copious, large, of a peculiarly vivid light- 
green: leaflets thin, ovate-lanceolate to lanceolate, acuminate 
but the very apex obtuse, entire or more or less plainly sinuate- 
lobed, the terminal 2 to 3 inches long, the laterals shorter and 
unequal-sided, both faces glabrous but the petioles pubescent: 
panicles slender, ample and many-flowered, erect or ascending: 
fruit unknown. 
Santo Catalina Mountains, Arizona, 5 May, 1894, J. W. 
Toumey. 
T. Arizonicum. Slender as the last, the branches tortuous 
but not geniculate, neither showing only aerial roots: leaves 
larger, dark green, firm and subcoriaceous, the leaflets elongated- 
oval, abruptly tapering to an apex, nevertheless, very obtuse, the 
terminal 24 to 44 inches long, the pair not very inequilateral, 
all entire, glabrous above, hirtellous along the veins beneath but 
hardly as to the petiolules: panicles small, seldom of much 
more than one raceme: fruit unknown. 
Fort Huachuca, Ariz., spring of 1890, Dr. Edw. Palmer. 
T. EXIMIUM. Branches long, slightly tortuous, evidently 
more or less reclining, only the growing parts seen, these not 
striate, greenish-gray, velvety-puberulent : leaves 5 or 8 inches 
long, rather short-petioled; terminal leaflet 2} to 34 inches long, 
