CATALOGUE OF SPECIES. 75 



Fremontodendron is one of the characteristic plants of the chaparral holt, in the 

 higher and more densely wooded parts of that helt growing us a shrub 1.5 to 2 meters 

 high; in the lower parts, when isolated, often attaining the dimensions of a small 

 tree. 



LINACE.33. 



Linum lewisii Pursh, Fl. i. 210 (1814). Type locality, "in the valleys of the 

 Rocky-mountains and on the. banks of the Missouri." 



Specimens were collected by Mr. Fnnston near the head of Wancoba Canon, Inyo 

 Mountains (No. 1788.) The plant was also abundant about our camp in the Sierra 

 Nevada, between Mineral King and Farewell Gap. 



Linum micranthum Gray, Proc. Amer. Acad. vii. 333 (1868). Type locality, "on 

 Mount Bullion, Mariposa Co.," California. 



Between Kernville and Havilah (No. 1048). This species was described by Gray 

 as "petalis albis basi utrinque subunidentatis," but l>y TreleaBe 1 as with petals 

 "not toothed." The basal teeth that occur in the related species are really repre- 

 sented in this one only by an undulation on either side of the base of the petal. 

 In our specimens all the ilowers examined are without the median appendage of the 

 petals. 



ZYGOPHYLLACEiE. 



Larrea tridentata (DC.) Prodr. i. 706 (1824), under ZygophylUm, Type locality, 

 "in regno Mexicano." 



The plant was tirst described under its present genus by Moricand, PI. Nouv. 

 Amer. 71 (1833-16), as Larrea mexlcana, under which name it has since passed. Fre- 

 mont, in the narrative of his report of the exploring expedition made in the years 

 1842-1844, puhHshed in 1845, in describing his entrance into the Mohave Desert 

 through Tehachapi Pass, says: "Several new plants appeared, among which was a 

 zygophyllaceons shrub (ZyyophyVum Calif ornk-um, Torr. &, Frem.) sometimes 10 feet 

 in height; inform, and in the pliancy of its branches, it is rather a graceful plant. Its 

 leaves are small, covered with a. resinous substance; and, particularly when bruised 

 and crushed, exhale a singular, but very agreeable andrefreshing odor." This de scrip- 

 tion was not, however, included in the botanical report appended under the author- 

 ship of Torrey and Fremont, undoubtedly from the facts stated by Torrey in an intro- 

 ductory note', that the part of Fremont's collection which escaped destruction was so 

 badly damaged that only a lew of the most important species were published, Fre- 

 mont's description quoted above, however, designates the plant definitely, and the 

 name stands as a synonym. De Candolle's specific name refers to the tridentate 

 (but obscurely so) character of the petals and stamen-scales. 



The original description of Zygophyllum tridentatum (see reference above) says " foli- 

 olis obovatis villosis," a fact which, taken with the type locality, suggested that De 

 Candolle's plant was not the same as that, which occurs in the United States, although 

 quoted as identical by Gray, Watson, and Hemsley. In our specimens the leaflets are 

 usually lanceolate-falcate, or at their widest obliquely oblong, and are nearly glab- 

 rous, but an examination of other specimens showed the hairiness to be very vari- 

 ablej while one specimen from the State of Tamaulipas, Mexico, has obliquely obovate 

 leaves agreeing with De Candolle's description. In 1848 Engelmann published the 

 United States plant as Larrea glutinosa, in Wislizenus's Memoir of a Tour to Northern 

 Mexico. Through the kindness of Dr. Casimir de Candolle I have been able to ex- 

 amine a tracing of the original plate upon which the description was founded. There 

 can be no doubt that it is the common Mexican form of our well-known creosote 



bush. __ 



i Trans. St. Louis Acad. v. 19 (1887). 



