to the Rocky Mountains. 207 



Desc. Root annual. Stem 6-8 inches long 1 , dichotomously branched 

 from the base, thick and rig-id, deeply striate, smooth. Leaves all pal- 

 mately divided, rigid ; the segrnents oblong, or lanceolate, about three- 

 fourths of an inch long, incisely serrate, the midrib prominent beneath. 

 Heads growing from the forks of the stem, and terminal, sessile, about 

 half an inch in diameter, shorter than the involucrum. Chaff of the recep- 

 tacle 1 nceolale, acuminate, carinate. Flowers small, white? Calyx with 

 pungent segments. Gcrmen squamose. 



Hab. On the Canadian. 



178. Sidm latifolium, L. Roem. and Schult. vi. p. 331. 

 Tor.jl. i. p. 31 1. Base of the Rocky Mountains. 



119. Hkiiacleum Sphondylium, L. JVutt.gen. i. p. 181. 

 On the Missouri. 



Obs. Besides the above Umbellifera?, there was in Dr. 

 James' Herbarium a small species collected on the Rocky 

 Mountains, which cannot be determined for want of the ripe 

 fruit. It is not described by Pursh, Nuttall, or Kunth ; and 

 my learned friend Professor Hooker, informs me that it is 

 new to him. The following is an imperfect description: — 

 Root perennial, thick, ligneous. Stem very short, imbricated 

 with the vestiges of leaves, cespitose. Leaves pinnate, smooth ; 

 leaflets 3-4 pairs, distinct, deeply o-parted ; the divisions lan- 

 ceolate, acute, entire. Peduncle subradical, about 23 inches 

 long, smooth, naked. Umbel compound ; rays 3-5, very 

 short. Universal involucrum ; partial 5-6-leaved ; leaflets 

 linear-lanceolate, as long as the flowers. Flowers minute, 

 sterile and perfect, intermixed? crowded. Calyx 5-toothed ; 

 the dentures subulate. Petals yellow, equal, acute and in- 

 curved at the apex. Stamens and styles divaricate. Germen 

 ovate, deeply sulcate. Immature fruit with three prominent 

 ribs on each side. 



Vol. II. 25 



