NORTH AMERICAN SPECIES OF CEANOTHUS. 107 



In the main, the limitation and descriptions of species in 

 Mr. Watson's monograph, and his references to literature, 

 in the Index, are so accurate as to require little alteration; 

 but after repeatedly going over the genus as represented in 

 the Gray, Engelmann, and Torrey herbaria, and in the ex- 

 tensive collections of the California Academy of Science, 

 and the United States Department of Agriculture, as well 

 as the fine private herbarium of Mr, J. C. Martindale, it has 

 seemed to me that Ceanothus is capable of subdivision into 

 more natural groups than have yet been proposed, and the 

 following is offered as a tentative arrangement of our spe- 

 cies, I shall be very grateful for specimens and notes eluci- 

 dating doubtful species, and I desire here to express my 

 obligation to the botanists who have already placed public 

 or private collections in my hands for study. 



A. Leaves alternate, not spinesceut, glandnlar-toothed or occasionally 

 entire; stipules thin, often subulate, fugacious; fruit sometimes 

 keeled or crested on the back of each segment, but not bearing 

 prominent dorsal horns. — Euceanoihus. 



a. Inflorescence on leatiess lateral peduncles borne on the 



old wood. 



1. C. SANGUINEUS, Pursh. Fl. Am. Sept. i. 167; Wat- 

 son, Proc. I. c. 334, Index, 166. — British Columbia to Idaho 

 and California. 



b. Inflorescence on leafy shoots of the present season's 



growth. 



* Flowers white, in small simple corymbose clusters 

 terminating mostly leafy spineless twigs: leaves 

 very small (2 to 8 mm. long), 3-nerved. — Atlantic 

 species. 



2. C. MiCROPHYLLUS, Michx. Fl. i. 154; Watson, l. c. 335. 

 Georgia to Florida. 



