GERANIACEAE 



Erodiu.rn have been introduced into this country and ive have one native 

 one. All of these arc inferior to E. deuterium. It is worthy of 

 note that E. texanum, our common native species, is frequently at- 

 tacked by what appears to be an erinose mite, or at any rate by an 

 organize which makes maple leaves. Eh_ cicutarium seems to be free 

 of this trouble. 



ZY60PHYLLACEAE 



Choisya dumosa, Starleaf, is a low shrub growing in protected 

 places in canyons and on stoop slopes in west Texas, southern New 

 Mexico and southern Arizona and extending into Mexico. It has 

 finely divided remarkable glandular leaves and fragrant white flow- 

 ers capable of perfuming whole canyons. The bushes are rather ten- 

 der and difficult to propagate. They are suited for erosion control 

 work in partially shaded north-facing slopes. They should be excel- 

 lent ornamentals, particularly in shaded roc:-: gardens. 3tudi.es 

 should bo made of the oil and rosin content of the foliage. 



Thamno sma montana is a very curious, nearly leafless shrub 

 with green, extremely glandular stems and purple flowers. It is 

 not uncommon in the foothills of the southwest. Since it has a foul 

 odor and. is so extrenelv glandular, it may contain valuable oils or 

 resins. Nothing larger than a bug will condescend to eat it and 

 it is of no value for erosion control. 



Thamno sma texana, slightly resembles T. mo ntana but is a much 

 smaller plant and less offensive. It lias a more limited range, being 

 confined in this country to western Texas and southern New Ilexico 

 and Arizona. It is valueless for forage and practically so for ero- 

 sion control. 



Ptelea trifoliata, Trefoil, is a shrub very widely distributed 

 in the west and southwest. The name, P. trifoliate covers a great 

 variety of forms and it is probable that it should be considered 

 two or more distinct species. These shrubs are frequently abundant 

 on north-facing slopes and in canyons. In no place, however, can 

 they be considered of distinct value for erosion oontrol. They 

 should be interesting additions, however, to shrub arboreta and for 

 ornamentals in yards. The trifoliate leaves are rather foul-smel- 

 ling and the fruits have wide wings somewhat similar to those on 

 the Elm. The plants are not palatable to livestock. 



Lar rea tr identa ta or Creosote Bush is one of the most common 

 shrubs in the southwest from western Texas to southern Utah, Nevada 

 and California. It extends also into Mexico, It occupies hundreds 

 of square miles in almost pure stands today whore it was only scat- 

 tering fifty years ago.' This is commonly the result of overgrazing. 



