324 CALIFORNIA ACADEMY OF SCIENCES. 



"On the sandy flats of the San Juan." 

 My specimens came from the latter locality. It was 

 abundant but with fruit immature. 



138. Euphorbia Fendleri Torr. & Gray, Pac. R. R. 

 Rep. ii, 175. 



Type locality: "Big Springs of the Colorado." (No. 

 800 of Fendler's New Mexican collection.) 



Collected on the sand-covered rocks, near the head of 

 Willow Creek. 



139. Celtis occidentalis L. Sp. PL, 1044. 

 Habitat: " In Virginia." 



Collected near the head of Willow Creek. 



140. Quercus undulata Torr., Ann. N. Y. Lye. ii, 248, 

 t. iv. 



Type localities: "Sources of the Canadian and the 

 Rocky Mountains." 



This was abundant in Butler Wash; low and spreading 

 or taller and growing in thickets. Collected with young 

 fruit from the taller bushes, the low ones being barren. 



141. Quercus Gambellii Nutt., Journ. Phil. Acad. Sci., 

 N. S., i, 179. 



Type locality: "On the banks of the Rio del Norte." 

 Two forms were collected. 



142. This form, collected at Butler Wash, has large 

 obovate leaves with blunt divisions; cups of the immature 

 acorns 15 mm. in diameter, acorns exserted 7 mm. 



143. This form from McElmo Canon is similar to =^. 

 venustula Greene, N. Am. Oaks, pt. 2, 69. The acorns, 

 as he notes, mature earlier, but in this instance the differ- 

 ence is due to locality, as I noticed other plants along 

 McElmo Creek more mature than the same species in 



