184 



Lliiii coitlalc tt) iLMiifonii, half to oxer an inch broad, 8 to o-hihcd 

 (lobes entire or toothed), on long slender petioles: umbels J to 4- 

 flowered, on short peduncles: fruit about a line long, sessile or 

 nearly so. (I'ig. 1<>0. ) — B. tcncra Sprcno-. /,'. gcraii'ilfoJia 

 Cham. «I^ Schlecht. B. nodijiora Presl. 



Damp shady places, from the Sacramento Vallpy, California, aiul south- 

 ward, extending into Arizona (Priiigle) and Texas (Hall, Wn'f/h'. Mins 

 f'roft). Fl. April and May. 



58. IIYDROCOT^'LI-: Linn. Gen. n. 325.— Low herba- 

 ceous perennials, growing in or near water, with slender creeping 

 stems, orbicular-peltate or reniform leaves, and small white flow- 

 ers in simple or proliferous umbels. 



The strong lateral llattening of the carpels and the prominent hypo- 

 dermal oil-bearing layer of tliis gtjnus are strilcingly different fronx those 

 of any other of our genera. In the European H. (•(*7(/.-f/-/.'* the oil-bearing 

 layer brealcs through the epidermis in places, covering the fruit with oil- 

 vesicles. 



* Fruit with pericarp tJiiii except at the broad tJiiek corky 

 dorsal and lateral ribs: i/ivoh/crc of short ovate bracts: leaves 

 orbicular-peltate^ crcnate: peduncles as long as petioles^ both from 

 slender creeping rootstocks. 



T Prnit )iotcJied'^ at base and apex ; intermediate ribs cork}'. 



L H. umbellata L. Spec. 284 Descending branches of 

 the rootstock with round tubers: umbels many-Howcred, simple 

 (sometimes proliferous); pedicels 2 to 6 lines long: fruit strongly 

 notched, 1 line long, about 1^4 lines broad, with dorsal ribs prom- 

 inent but obtuse. ( Fig. 16L ) 



From Massachusetts to Florida, westward to Minnesota and Texas, and 

 extending into Mexico. 



Forms collected on ballast near Philadelphia [Martiiididi'), Port Eads, 

 Louisiana (L(0(f//o/,s), and Vancouver Island iAfacoun), are unusually pro- 

 liferous, sometimes so much so as to give the impression of compound 

 umbels. 



2. H. prolifera Kellogg, Proc. Calif. Acad. i. 15. Tuber- 

 ous as in the last: umbels mostly proliferous, with 5 to 2()-flovvered 

 whorls; pedicels 1 to 8 lines long: fruit but slightly notched, a line 

 long or slightly broader, with dorsal ribs prominent and more 



7 This notchinic ii):iy not be uppurint t-xci-pt in 



