204 ORDER I. RANUJ^^CULACE^E. 



nia numerous, ovate, pointed, compressed, smooth, striated, or 

 tuberculated, arranged in a cjlindric or globose head. 



1. R. aquat'ilis, (L.) Stem floating, long, slender, jointed. Leaves 

 submersed, capillary, alternate, petioled. Cali/x glabrous. Petals 

 white ; claw yellow, with a conspicuous pore. Achenia tra-nsversely 

 wrinkled. — ^ . June to Aug. Ponds and streams. Car. and Geo. 



a. Leaves undivided, fotcers yellow, carpels smooth. 



2. R. laxicau'lis, (T. ct G.) Stem weak, much branched, declined, 

 rooting at the lower joints, glabrous. Leaves smooth, linear-lanceolate, 

 or elliptical, oblong ; upper ones linear. Peduncles opposite the leaves, 

 1 — 2 inches long. Carpels with a subulate beak in a globular head. 

 Petals mudi longer than the calyx, slender at the base. — ^ . Ditcher 

 Car. and Geo. July. 



8. R. pusil'lus, (Poir.) Stem decumbent, little branched, glabrous. 

 Leaves on long petioles, entire or denticulate, obtuse ; lower ones 

 ovate or subcordate ; upper ones linear-lanceolate. Peduncles opposite 

 the leaves, 1-flowered. Sepals ovate, obtuse. Flowers small. Petals 

 small, nearly round. Pore at the base of the limb of the petal. Sta- 

 mens few. Styles none. Achenia ovate. — Yellow. '^ . Very common 

 in wet soils. March. 



b. Leaves divided. 



4. R. ABORTi'vus, (L.) Stem glabrous, simple, or branching. Radi- 

 cal leaves on petioles, cordate, reniform, or broadly ovate ; sometimes 

 3-parted, crenate ; cauliue ones 3 — 5-parted, with long, entire, linear 

 lobes. Sepals glabrous, reflexed, longer than the petals. Floicers small, 

 scale large. C'ar/)e/« in a globose head. — ^. Common in the middle 

 regions of Geo. and Car. May. 



5. R. scelera'tus, (L.) Boot fibrous. Stem 1 — 2 feet high, fistulous, 

 thick, leafy. Leaves on petioles, lower ones with petioles 4 or 5 inchea 

 long, sheathing, 3-parted, radical ones with the divisions 3-lobed and 

 obtusely incised, upper ones with oblong linear entire lobes. Sepals 

 reflexed, colored. Flowers small, solitary, generally opposite the leaves ; 

 petals longer than the sepals, shining. Stamens 12 — 15, shorter than 

 the petals. Carpels small, numerous, in a cylindrical head. — ^ . Com- 

 mon in the Ioav country. May. 



6. R. Pur'shii, (Richards.) Submerged leaves filiformly 2 or 3- 

 chotimously dissected, with segments flat ; emersed ones reniform, 3 — 

 6-parted, the lobes variously divided. Petals twice as large as the re- 

 flexed sepals. Carpels in globose heads, smooth, with a short and 

 straight ensiform style. — In ponds and muddy places. N. Car. and 

 Lou. Torrey & Gray. 



7. R. ke'pens, (L.) Stems prostrate and creeping, sometimes erect. 

 Leaves trifoliate, segments cuneate, 3-lobed, incisely toothed, middle 

 one petioled. Calyx spreading. Carpels with a straight point. This 

 plant is very variable : sometimes villous, at otliers glabrous. Floicers 

 vary in size, and number of petals from 5 — 8. The R. Nitidus of 

 Elliott, we believe, is only a variety of this, as we have seen it assuming 

 all the peculiarities of that plant, with good reason to believe it was 

 the one described. — In wet grounds, very common in Middle Geo. 



8. R. palma'tus. Carolinia'nus. Stem erect, 12 — 18 inches high, 

 hairy, hair above appressed, below spreading ; branches long, 1-flowored 



