410 DESCRIPTIONS OF NEW SPECIES 



tracted, five to eight or ten-flowered, the pedicels and involucrum bracteolate; sepals linear, acute, 

 about twenty, often with dark purple sphaceolous points. Rays about eight. Pappus shorter than 

 the florets; achenium smooth. Considerably allied to S. pratensis, but nearly smooth, also 

 to the S. papposum. There is a specimen very similar to our plant from Altai, sent to Dr. Schwei- 

 nitz, but without any certain name. 



Senecio * megacephalus; %, stem low, densely lanuginous at base; leaves de- 

 ciduously lanuginous, oblong-lanceolate, entire, cauline amplexicaule, linear- 

 lanceolate, acute; corymb of three to five bracteolate, large capituli; involu- 

 crum pubescent, of twenty to twenty-four linear, acute sepals, tipped with tufts 

 of hairs; rays pale yellow, ten to twelve, scarcely as long as the involucrum; 

 achenium smooth, with about ten striatures; dentures of the florets papillose. 



Hab. On the plains of the Platte, towards the Rocky Mountains. Nearly allied to S. alpestris. 

 About six to eight inches high; the leaves perfectly entire, more or less pubescent beneath, lower 

 leaves with long petioles. Capituli very large, for the size of the plant, about as large as those 

 of the common bur, [Arctium lappa.) 



Senecio *fastigiatus; il, nearly smooth, or somewhat arachnoidly tomentose; 

 stem erect, simple, grooved, the summit compoundly corymbose and fastigiate; 

 leaves lanceolate or linear-lanceolate, entire or distantly serrulate, acute, the 

 radical long petiolate, cauline few, sessile, linear, attenuated below, the upper- 

 most amplexicaule; branches of the corymb two or three-flowered, pedicels 

 elongated, bracteolate; involucrum turbinate, nearly naked, sepals twelve to 

 fifteen; rays oblong, nearly entire, about eight, longer than the involucrum; 

 achenium smooth. 



Hab. The plains of Oregon, near the Wahlamet. A tall, rather slender species, two to three 

 or more feet high, with a running root. Lower leaves with their petioles more than a span long, 

 not more than half to three quarters of an inch wide. Leaves of the stem very small and distant, 

 giving the plant a remarkably naked appearance. Sepals yellowish, linear, and acuminate. Rays 

 long, (often twice as long as the involucrum,) few, and bright yellow, linear-oblong, slightly 

 toothed, attenuated below, and sometimes tubular. Tubular florets, about twenty, the teeth ovate, 

 acute, nearly smooth, exserted beyond the pappus. A few irregular slender bractes beneath the 

 involucrum. 



Senecio "^exaltatus; %, more or less hirsute with white hairs; the radical 

 leaves nearly smooth; stem tall, robust, nearly cylindric and grooved; lower 

 leaves oblong-lanceolate, unequally and glandularly serrate, rather broad and 

 long petiolate; upper leaves small and amplexicaule, incisely, and sometimes 

 deeply serrate; corymb compound, many-flowered, fastigiate; involucrum cam- 



