BOX-ELDERS, REAL AND SO-CALLED 139 
other species. Seven leaflets are as rare in the eastern part as 
five are in the Rocky Mountain plant, but even 7-11 leaflets are 
far from rare in the midland Box-elder. R. Negundo has pubescent 
fruit bodies, those of R. Nuttalli are perfectly glabrous at maturity. 
The fruit is usually not or but little attenuate at the base. Leaves 
of the eastern plant dry to an olive brown, the veiny thick leaves 
of the midland plant dry greenish, the mesophyl on the lower 
surface of R. Nuttallii is pale glaucous and even secondary network 
of veins very prominent. I have never seen in the other species 
a near approach to the bipinnate leaf of our midland plant. Entire 
branches often are found that have never fewer than eight to 
eleven leaflets to the leaves. 
3. RULAC INTERIOR (Britton). 
Acer interior Britton, 1908.* 
Rulac texana Small, 1903+, Secundum descriptionem, vel 
saltem in parte. 
Negundo Fraxinus Bourg., 1859¢ probabiliter, sed nomen 
nudum. 
There seems to be no need of repeating Dr. Britton’s characters. 
The tree is together with Rulac Nuttallii one of the commonest 
of specimens in our herbaria, and together with it more numerously 
represented than all the others taken together. 
4. Ruiac Kincu (Britton) 
Acer Kingi Britton, 1908.$ 
5. RULAC CALIFORNICA (Torrey & Gray). 
Acer californicum (Torrey and Gray) Dietrich. || 
Negundo californicum Torrey and Gray. 1838, 1840.4] 
Inclusive of Rulac californica var texana Pax Rulac texana 
(Pax) Small. This plant is only a less densely pubescent form of 
R. californica and can hardly be considered as a variety, since 
even FR. californica varies more in other ways. 
Native of California along the coast of the Pacific Ocean, 
especially in the southern part of the State extending into Mexico. 
* Britton, N. L. North American Trees, (1908), p. 655. 
eee: TP eleclae = hc. p: 656. 
leDietiich, sD soya i 1283" 
{| Torrey & Gray, Fl. N. Am. L., (1838-1840):, p. 250. 
