IV. A Study of N'orth American Gerakiacbae. 

 By William Trelease. 



(Kead Feb. 16, 1887.) 



JLlsT the following- pages, I have brought together desci-iptioiis of our species of Gera- 

 niaceae, and a few biological notes on them, together with references on their pollination, 

 dissemination, etc. IN'o general revision of our species of this order has been undertaken 

 since the publication of the first volume of Torrey and Gray's Flora of North America, 

 1838-40. The systematic literature and the synonymy of ISTorth American species will 

 be found in "Watson's Bibliographical Index to North American Botany, i, 119, while 

 the more important papers on the order as a whole and its subdivisions are indicated in 

 Bentham and Hooker's Genera Plantarum, i. A synopsis of the larger species of Ge- 

 ranium, by Engelmann, appears in Gray's Plant. Fendler., pp. 26-7. 



I am indebted to Professor Gray and Mr. "Watson for the free use of the Gray herba- 

 rium of Harvard University, and for many helpful suggestions ; to Dr. Britton for the 

 specimens contained in the Torrey and other herbaria of Columbia College; to Miss 

 Carter for access to the herbarium of this Society; to Professors Prentiss and Dudley 

 for the specimens in the Horace Mann herbarium of Cornell University, as well as for a 

 large suite of duplicates of the eastern species ; and to Dr. George J. Engelmann for 

 forwarding me the specimens in the Engelmann herbarium of St. Louis. A number of 

 friends have also favored me with smaller collections, chiefly of eastern species, the most 

 valuable of these being a suite of specimens of Oxalis recurim, collected about Cincin- 

 nati, by Mr. C. G. Lloyd, and a Nuttall specimen of Oxalis pumila from Mr. J. H. Red- 

 field, of Philadelphia, a fine suite of O. Suksdorjii from Mr. L. F. Henderson, of Port- 

 land, Oregon, and flowers from the type specimens of 0. Dillenii, at Oxford, secured by 

 Professor Gray. 



GERANIACEAE, Bentham and Hooker, Genera, i, p. 2G9. 



Annual, biennial, or pei-ennial plants; ours herbaceous or merely suftVutescent. Leaves 

 alternate or occasionally opposite or pseudo-verticillate, simple, divided, or compound, 

 mostly cut-toothed. Inflorescence sometimes evidently cymose, or the flowers solitary 



MEMOIRS BOSTON SOC. NAT. HIST., VOL. IV. 11 (^U 



