AND GENERA OF PLANTS. 433 



Hab. Plains of the Wahlamet, near its estuary. With the habit of a Troximon. Flowers pale 

 yellow. Scape six inches to a foot high. Sepals linear-lanceolate, smooth, the outer two series, 

 for the most part, slightly pubescent. In ;3. the leaves are twelve to fourteen inches long, the scape 

 two feet, Avith the involucel or caliculum squarrose, and sometimes several inches long. 



Stijlopappus ^elatus; smooth, the base of the scape pilose; leaves very irre- 

 gularly and deeply pinnatifid, the segments long and linear; involucrum widely 

 carapanulate ; leaves of the caliculum lanceolate, the lower series hirsute ; stipe 

 rather thick, a little more than the length of the elongated achenium. 



Hab. With the above, which it closely resembles, but appears to be a larger plant, the scape 

 from twelve to fourteen inches high ; but the principal distinction is in the achenium, which is 

 twice as large, with a much thicker stipe. The outer series of tabescent achenia are also pubescent, 

 and there appears, likewise, to be another inner, abortive, smooth series. Flowers almost exactly 

 like those of Troximon glaucum. 



TROXIMON. (NuTT. Gen. Am., non GiERTNER.) 



Capitulum many-flowered. Involucrum imbricate, subcampanulate, divisions 

 lanceolate, distinct, or united at base. Receptacle naked, punctate. Ache- 

 nium subterete, with ten obtuse ribs, attenuated above into a somewhat simi- 

 larly striated, and rather short, thick rostrum. Pappus copious, setaceous, 

 persistent, widest at base, longer than the achenium, and scarcely scabrous. 

 — Stemless perennials, with fusiform roots, and mostly entire, linear, smooth, 

 sublanceolate leaves. Scapes terete, exserted, one-flowered; flowers yellow 

 or rose-coloured. Obs. The only species of this genus known to Gsertner, 

 T. lanatum, is now referred to Scorzonera, the name thus unoccupied may, 

 therefore, still be retained for the American species. 



t Achenium terete, shortly rostrate, ruith obtuse ribs. 



Troximon glaueum. The involucrum is usually smooth, the divisions in 

 about three series, the outer shorter, all of them lanceolate and acute. 

 Hab. On the plains of the Platte, and Missouri, about the Great Bend. 



Troximon marginatum. The scape taller than in the preceding. Divisions 



of the involucrum in about two series, with the outer broader and as long as 



the inner, all of them linear-lanceolate. Achenium subcylindric, somewhat 



narrower at the summit, pale straw-colour, with ten obtuse ribs, the basal cica- 



VII. — 5 I 



