SIMARU3ACEAE 



stock; and ability to withstand severe abuse. The Tree of Heaven 

 has been planted along the highway in eastern Oregon as an orna- 

 mental with complete success and it is used as an ornamental shade 

 tree along city streets. Thus far it has been used to a very 

 limited extent, if at all, in erosion control work in the southwest. 



BIJF.SERACEAE 



Elaphrium microphyllum, Elephant Tree. In the early days of 

 the Spanish invasion of the southwest this small tree supplied vast 

 quantities of bark which was shipped to Spain for its tannin. The 

 tree is much more abundant in Sonora than it is in Arizona. In the /• 

 hills southeast of Yuma, along the Mexican border, however, this 

 curious tree is rather abundant. It resembles a pepper tree except 

 that the compound leaves are very small and the fruits are borne 

 singly on the twigs instead of in long panicles. The trees are 

 low and squatty with trunks which are very thick at the base and 

 which taper abruptly upward. The small fruits and leaves arc very 

 glandular and quite fragrant with a pungent odor, When and if our 

 activities spread into the hot regions south of the Gila, this tree 

 should occupy a place in our program. Yvhercvcr it grows oranges 

 and probably avocados will grow if given water. 



POLYGALACEAE 



Polygala spp., Milkworts. Most of the Polygalas are of no 

 significance for forage or for erosion control. Some are annuals 

 with possibilities as ornamentals in cultivation. One, P. poly c ladon , 

 is a rather abundant shrub in the region of Vermillion Cliff s, Arizona, 

 but it is very thorny and apparently not browsed. P. rusbyi is a 

 low perennial with a deep root and very short, somewhat spreading 

 woody caudex which has handsome creamy, pinkish purple flowers 

 rather large for a Polygala. This might be a good erosion control 

 plant if it grew abundantly enough. It is a rare plant found on the 

 flats between Kingman and Seligman in Arizona, and doubtless else- 

 where. P. macradenia, however, is an important browse shrub which 

 has a rather wide distribution in northwestern Arizona and adjacent 

 regions, and in the Santa Rita region of southern Arizona. It is 

 a deep-rooted, very low shrub with spreading caudex, small leaves 

 and purplish flowers. At the base of tho Kofa Mountains it is 

 abundant and Is always browsed very close by mountain sheep. 

 Professor Thomber reports it to be a good browse plant in the 

 Santa Ritas. This plant has not been grown in the nurseries and 

 nothing is known of its propagation possibilities. 



EUPHORBIAS EAE 



Bernard ia myricaefolia is a shrub three to five feet high 

 with small, thick grayish leaves with Irregular dentate margins and 



-99- 



