OP ARTS AND SCIENCES. 367 



++ ++ Scapose from filiform rootstocks, oligogynous, and long-styled. 

 R. Lapponicds, L. 



-t- -I- -H- Uliginous or subaquatic, fibrous-rooted, with entire or merely 



denticulate or crenulate and petiolate leaves. 



++ Akenes beakless or nearly so, dull : subannuals, sometimes rooting 



from the lower nodes, but hardly thereby perennial. 



= Petals 1 to 3 or 5, not over a line long: stamens 5 to 10. 



R. TRACHTSPERMUS, Engelm. PI. Lindh. i. 3, no. 2 (not Ell.),excl. 

 var. Lindheimeri. Carpel-heads oblong or cylindraceous. — Louisiana 

 and Texas. 



R. PUSiLLiTS, Poir. — New York to Texas. R. Bonariensis, Poir. 

 is very near to this, and of no older date. R. fontcmus, Presl, of S. 

 Italy, is also near, and perhaps was introduced from America. 



Var. Lindheimeri. A small form, with akenes more papillose- 

 roughisb, but traces of this are not uncommon in R. pvsillus. — R. 

 trachyspermus ? var. Lindheimeri, Engelm. PI. Lindh. i. 3 ; Torr. 

 Pacif. R. Rep. iv. 62. — Galveston, Texas, Lindheimer. California, 

 in Najja Valley, Bigelow, and San Rafael, J. P. Morse, from E. L. 

 Greene. Widely distant stations ; but the plants seem to be specifi- 

 cally the same. 



= = Petals 5, bright yellow, surpassing the calyx, 1 to 3 lines long: 

 stamens numerous : style wholly deciduous. 

 R. OBLONGiFOLius, Ell. R. pusillus, var. oblongifolius, and R. 

 Flammida, var. laxicaulis, Torr. & Gray, Fl. i. 16, 17. R. Texensis, 

 Engelm. PI. Lindh. i. 2. — Illinois and S. Carolina to Texas. 



++ -H- Akenes subulate-beaked (but beak sometimes deciduous or re- 

 duced to an apiculation), in a globular head: petals 5 or more. 

 = Perennial by rooting from the nodes of creeping or the lower nodes 

 of ascending stems, wholly fibrous-rooted. 



R. hydrocharoidks. Gray, PI. Thurb. in Mem. Amer. Acad. v. 

 306. — S. Arizona, Thnrber, Capt. Smith, Rothrock, Lemmon, to 

 Southern California east of the Sierra, KeJlogrj. R. stolonifer, Ilemsl., 

 of Northern Mexico, is related to this, but is much smaller-flowered. 

 Both have cordate lower leaves. 



R. Flammula, L., of which we have not the type, but only var. 

 iNTERMEDius, Ilook. (from Lake Ontario to California and north- 

 ward), and var. reptans, E. Meyer. 



R. ambiCtENS, "Watson, Proc. Am. Acad. xiv. 289, & I'.ibl. Iiid. 16. 

 R. Flammula & R. Lingua of Pursh, &c. R. Flammula, Torr. & 



