MEMOIES FEOM THE DEPAETMENT OF BOTANY OF COLUMBIA COLLEGE. 15 



The appended list/ embodying all that is at present known to occur in the genus, in 

 the fossil state, has been furnished by Dr. F. H. Knowlton, of the United States Na- 

 tional Museum. 



While studying a collection of fossil plants with Mr. Hollick last winter, I detected 

 among other new forms a Polygonum, remarkably distinct and well preserved. This col- 

 lection was brought from Florissant, Colorado, a few years ago by Dr. Britton, and depos- 

 ited in the Geological Museum of Columbia College. Nothing concerning this group has 

 been, recorded in North American paleobotany, but there can be no doubt about the 

 member under consideration. It belongs to the subgenus Persicaria, and its nearest liv- 

 ing relative is P. emersuvi. The resemblance to that species is striking in the characters 

 of the stem, the way in which the petiole is joined to the ocrea, the leaf, and even in the 

 forking of the secondary nerves of the leaf-blade. 



1 Polygonum antiquum Heer, FL Tert. Helv. 3: 184, t. 79, f. S7 (1859). 

 Polygonum caediocaepum Heer, Fl. Tert. Helv. 3: 184, t. 155, f. ^5-S7 (1859). 

 , Polygonum convolvuloides Conwentz, Fl. d. Bernst. 2: 48, t. 4, f. 2S-26 (1886). 

 Polygonum ouspidatum Sieb. & Zuco. (fossil) Nathorst, Foss. Fl. Japans, Pal. Abhandl. 4: (30) 224, t. 10 (26), /. 18 



(1888). 

 Polygonum Hydeopipee L. ? (fossil) Heer, Urw. d. Schw. 496, 616 (1865). 

 Polygonum Otteesianum Heer, Schweizerischen Natuif. Gesell. in Solothurn, Verhandl, 164 (1869). Fl. Foss. Arot. 



2: pt. 3 ; <. 11, f. S", U, 15; t. 13, f.-9-9*' (1870). 

 Polygonum Peesioaeia L. (fossil) Eeid, Quart. Journ. Geol. Soo. 48: 358 (1892). 

 .Polygonum eotundatum Heer, Climat. et Veg. Tert. 45 (1861); Urw. d. Schw. 352, 706 (1865). 

 Polygonum vivipaeom L. (fossil) Heer, Urw. d. Schw. 580, 760, 1. 12, f. 13 (1865). Schroter, Fl. d. Eiszeit. 26, 35, 



t. l,f.43-U{lS82). 

 Polygonum ? sp. Tasohe, Ber. Oberhess. Gesell. Naturkunde, 4: 94 (1854). 



POLYGONITES DBPEEDITUS Ett. Beitrage z. Kermt. Tertfl. Steiermarks, Sitz. Wien. Akad. 60: pt. 1, 58, t. S,f. 15 (1869). 

 POLYGONITES ULMAOEUS Saporta. Ami. Soi. Nat. Bot. (V.) 3: 92, i. 3, f. U (1865). 



