FLOWERING PLANTS AND FERNS OF ARIZONA 225 



distinguishable, even in sterile condition, from other southwestern 

 oaks. 



2. Quercus oblongifolia Torr. in Sitgreaves, Zufii and Colo. Rpt. 173. 



1853. 



Mohave County and mountains of Cochise, Santa Cruz, and Pima 

 Counties, up to about 6,000 feet, common in the foothills of desert 

 mountain ranges. Arizona and northern Mexico. 



Mexican blue oak. Commonly a small tree 5 to 8 m. (16 to 26 feet) 

 high, with a broadly spreading crown, but it may mature as a shrub at 

 higher altitudes. 



3. Quercus arizonica Sarg., Gard. and Forest 8: 92. 1895. 

 Yavapai County to Graham, Cochise, Santa Cruz, and Pima Coun- 

 ties, up to about 6,000 (exceptionally 7,400) feet, common. Xew 

 Mexico, Arizona, and northern Mexico. 



Arizona oak. A well-marked species in Arizona, although it 

 grades into Q. grisea Liebm. in Xew Mexico. It forms a tree up to 

 is m. (60 feet) high, with a trunk 1 m. (3 feet) in diameter, or it may 

 mature as a large shrub. 



4. Quercus grisea Liebm., Overs. Danske Vidensk. Selsk. Forh. 1854: 



171. 1854. 



White Mountains (Apache Comity) and Oak Creek (Coconino 

 Comity) to Cochise, Gila, and Maricopa Counties. Texas to Arizona 

 and northern Mexico. 



Gray oak. A small or large tree, reaching a height of 20 m. (65 

 feet) in moist, protected situations. It is one of the most difficult 

 of Arizona oaks to distinguish, intergrading freely in this area with 

 both Q. arizonica and Q. turbinella, although the much more abundant 

 typical forms of the 3 species are clearly distinct. The species reaches 

 the northwestern limit of its range in Arizona and is not an important 

 element of the flora there, whereas in Xew Mexico and western Texas 

 it is dominant in the "encinal" over large areas. 



5. Quercus toumeyi Sarg., Gard. and Forest 8: 92. 1895. 



San Francisco Peaks (Coconino County), near Prescott (Yavapai 

 County), much more abundant in Cochise and Santa Cruz Counties, 

 commonly 4.000 to 6.000 feet, type from the Mule Mountains, 

 Cochise County (Tourney in 1899). Arizona and northern Mexico. 



Tourney oak. A small tree usually less than 10 m. (33 feet) high, 

 or a shrub 1 or 2 m. high. Its characteristically very small, entire, 

 yellowish-green leaves, shiny above, mucronatcly acute, and densely 

 disposed on the branches, make it easily distinguishable from all other 

 species in its range. 



6. Quercus turbiuella Greene, Illus. West. Amer. Oaks 1 : 37. 1S89. 



Quercus dumosa Nutt. var. turbinella Jepson, Silva Calif. 218. 



1910. 

 Quercus subturbinella Trek. Xatl. Acad. Sci. Mem. 20: 95. 



1924. 



Almost throughout the State, 8,000 feet or (commonly) lower. 

 Colorado and Xew Mexico to California and northern Mexico. 



Scrub oak. This species centers in Arizona, where it is the most 

 abundant element of the chaparral, growing as a shrub or at most a 



