PAP IL I ORAC EAE 



species mentioned and forms much larger denser clumps. It has a 

 widely spreading crown, and a single plant frequently covers several 

 square feet. The root system seems to be superior to other species 

 discussed for the control of erosion. The leaflets are somewhat 

 silvery and the flowers are rose colored. It is probable that this 

 species is either one known previously only from Mexico, or one that 

 has not been described. It seems to be one of our most promising 

 plants for erosion control purposes. 



Dales, spinosa. Within our range this is the only species of 

 Daloa which becomes a tree. Its range is southwestern Arizona and 

 adjacent southern Nevada, southern California and adjacent Mexico. 

 Common throughout the southwest it is known as the smoke tree, and 

 when in blossom is one of the most striking plants of the desert, 

 being a solid mass of dark blue blossoms. The stems and twigs are 

 almost leafless but arc themselves green with a greyish tint. The 

 density of the sc grayish green twigs on the plant give it a dis- 

 tinct resemblance to smoke at a distance. This plant requires a 

 very hot dry climate and is doubtless unsuitcd for other sections 

 of the country than those in which it grows naturally. It should 

 be generally used in the dry southwest as an ornamental, 



Dalea emoryi is another Dalea occupying extremely dry hot 

 regions such as those about Yuma, It is a low straggling bush with 

 beautiful flowers and extremely glandular leaves, stems and flower 

 clusters. The oil or resin from this plant was formerly used by the 

 Indians as c dye and this use suggests the possibility that the 

 plant may contain valuable properties either from a pharmaceutical 

 or commercial oil standpoint. Owing to site and climate requirements 

 this shrub is rot likely to gain a place in a distinctly erosion con- 

 trol program. One very curious fact regarding this p^.art in the 

 region of Yuma is worth mentioning. It is subject to the attack 

 of a very curious parasitic flowering plant, Pilos cylis... Frequently 

 the stems are almost completely covered with this parasite, an in- 

 dividual plant of rhich is very little larger than the head of an 

 ordinary pin. It consists almost entirely of the flower. Superfi- 

 cially the parasitized Dalea looks as though it has been attacked 

 by a fungus disease or by a type of gall-forming insect. This 

 parasite is closely related to a flowering plant in the tropics 

 which produces the largest flower known to science, frequently two 

 or three feet across and is exceptionally beautiful. In this 

 case also, practically the entire plant consists of the blossom, 



Daloa polygodenia in general habit resembles D, emoryi but 

 on the whole it is a smaller more nearly prostrate bush. The" glan- 

 dular character of this plant suggests its use for dye and oil. In 

 natural distribution it is confined to the extreme desert sections 

 of southern Nevada and adjacent California. 



-37- 



