but they i^ro st) widt'ly diflereiiL tliiit they seem to tlesiu vc geiieric separu- 
tion. As this ean be deteruiiiied, however, only Jifter a detailed study of 
the numerous foreign species, we prefer to leave them as they are for the 
present. ^ 
* Perennial^ from a hraitchlng camiex : i/ivo^itcre of j to ^ 
ttnequal bracts \ in-oolnccls of ^ to 8 rather small orate bract lets: 
carpel rvith prominent ribs^ oil4nbes continnons about the seed- 
cavity and one in each rib : seed-face plane, 
1. B. Americanum. Radical leaves linear-lanceolate; can- 
line ones very variable, oblong to linear, more or less clasping: 
rays unequal % to 2 inches long; pedicels short. (Fig. 128.)— 
B. rannnculoides of American authors, not L. 
Alaska {Lay th Collie, Rothrock, Schwatka, Muir, etc.); mountains of 
1 1 1 0 o t/ e I i t a ); mountains of Montana and Yellowstone 
Pax'k {Coulter, Canby, Serilmer, Tu'eedy, Parry, etc.) FI. July and 
August. 
This species is so variable in foliage that varieties would seem admiss- 
ible. Resemblance to the European B. ranunen'oides is well shown bj'^ 
low forms with rather smali oblong thin leaves and quite pi’ominent bract- 
lets; while more abundant in collections ai’e the larger forms with elongated 
linear-lanceolate rather rigid stem-leaves and smaller bractlets. In the 
European species referred to, and to which our species has been heretofore 
referred, the oil- tubes are large and solitary, while in our species they are 
so numerous (about 23) as to be continuous about the seed-cavity. In 
habit there is a close resenriblanee to the European species- 
* * Annual’, involucre none,, involucels of j very conspicu- 
ous ovate mucronate bractlets : carpels with very slender ribs^ and 
no oil- tubes : seed-face somewhat concave. 
B. ROTUNDiFOi.ruM L., with ovate perfoliate leaves, is intro- 
duced from Europe, and is very common in fields and cultivated 
ground, from New York to N. Carolina, and westward to Ar- 
kansas and Missouri. (Fig. 129.) 
B. PROTUACTUM Link, which differs from the last chiefly in 
its tuberculate fruit, has been collected on ballast fTround near 
Philadelphia by Mr. Martindale. 
40. CH.EROPHYLLUM Linn. Gen. n. 858. Annu.als, 
in moist ground, with ternately decompound leaves, pinnatifid 
leaflets with oblong obtuse lobes, usuall}^ no involucre, involucels 
of mariy bractlets, and white flowers. 
