296 DESCRIPTIONS OF NEW SPECIES 
Tripolium * Oregonum, stem rather tall, flexuous, and divaricately branched ; 
cauline leaves long, linear, sublanceolate, nearly equal, acute, entire, scabrous 
on the margin; sepals linear-lanceolate, imbricate, slightly acute, herbaceous; 
rays narrow. 
Has. On the inundated banks of the Wahlamet; flowers very inconspicuous, somewhat fas- 
tigiate. 
Tripolium *divaricatum, stem rather naked, slenderly and divaricately 
branched; radical leaves spathulate, or lanceolate, subdenticulate; stem leaves 
above, very short and subulate, clasping; sepals subulate, acuminate, scariose, 
imbricate, and somewhat equal; achenium smooth, with four strie. 
Has. Inundated banks of the Mississippi, and in Louisiana, not uncommon. Very smooth, the 
radical leaves thick, flowers rather conspicuous, rays blue. Remarkable for its divaricate and 
naked branches. A plant very similar occurs on the coast of Cuba. 
Tripolium * occidentale, stem nearly simple, few-flowered, flowers large and 
corymbose; leaves all linear, subulate amplexicaule, here and there incisely 
serrate; involucrum loosely imbricate; sepals subulate, subherbaceous, nearly 
equal; rays as long as the disk, (pale blue;) achenium nearly smooth, scarcely 
striate, compressed. 
Has. By the margins of muddy ponds in the Rocky Mountains, seven thousand feet above the 
level of the sea. Root creeping, slender; stem slender, four inches to a foot high, often only one 
or two-flowered, seldom more than five or six. Leaves long and narrow, linear, entire, or with 
one or two pair of deep, incise serratures, almost approacing to a pinnatifid division; branchlets 
slender, one-flowered. ‘The flower as large as a daisy, with a simple series of pale blue, or pink 
rays. An alpine species, approaching the true Tripolium in the fruit being almost destitute of 
striation. 
Tripolium * frondosum, stem much branched, leaves linear, entire, amplexi- 
caule, rather obtuse; capituli fastigiate; sepals linear-oblong, loose and leafy, 
rather obtuse; rays numerous, very small and slender; achenium nearly smooth, 
about four-striate. 
Has. By muddy ponds in the Rocky Mountains, near Lewis’ River of the Shoshonee; rare. 
Growing partly in the water and mud. Apparently biennial, succulent, with very inconspicuous 
flowers, and an entirely leafy, nearly equal involucrum of about two series of leaflets. 
Tripohum subulatum. Allied to the preceding by its numerous small rays. 
Achenium slightly pubescent, compressed, with five strie. 
