272 UMBELLIFER^. Thaspium. 



Tribe IV. SESELINEM. Koch. 



Transverse section of the fruit orbicular, or nearly so. Carpels with five filiform or winged 

 rihs, of which the lateral ones are marginal, and either equal with or a little broader 

 than the others. Intervals with one or more vitt<B, very rarely without any. Seed 

 somewhat teretely convex on the back, fattish on the face. — Umbels perfectly compound. 



10. THASPIUM. Nutt. gen. 1. p. 196 ; DC. prodr. 4. p. 153. THASPWM. 



[ " From the Isle of Tliaspia, which gave name to the Thapsia of the ancients."* Nctt.] 



Calyx-teeth lanceolate or nearly obsolete. Petals elliptical, attenuated into a long inflexed 

 point. Styles slender, as long as the ovary, somewhat diverging. Fruit not contracted at 

 the sides, elliptical. Carpels convex, with 5 winged mostly equal ribs. Intervals striate, 

 with single vittae. Commissure with 2 vittae. Seed somewhat terete. — Perennial herbs. 

 Leaves ternately or biternately divided ; the radical ones sometimes cordate and entire. 

 Umbels terminal and opposite the leaves, without an involucre. Involucels lateral, small. 

 Flowers yellow or purple. 



1. Thaspium atropurpureum, Nutt. (Plate XXXIV.) Purple Alexanders. 



Radical leaves on long petioles, mostly cordate and undivided, crenately toothed ; cauline 

 ones ternately divided, serrate, terminal one ahva3's (and the lateral ones also in the lower 

 leaves) peliolulate ; umbels opposite the leaves, and terminal ; flowers dark purple ; winged 

 ribs of the carpel equal. — Nutt. gen. 1. p. 196 ; DC. prodr. 4. p. 154. T. cordatum, /3. 

 atropurpureum, Torr. ^ Gr. jl. N. Am. 1. p. 615. Thapsia trifoliata, Linn. sp. 1. p. 162. 

 Smj'rnium atropurpureum, Lam. diet. 3. p. 667; Pursh, f.. 1. p. 196. Cnidium atro- 

 purpureum, Spreng. in Schult. syst. 6. p. 418 ; Torr. fl. \. p. 307. 



Stem 1-2 feet high, smooth, terete. Radical leaves sometimes 2 - 3-lobed or ternately 

 divided, one or more of them usually entire, 1-2 inches in diameter. Cauline leaves petio- 

 lale ; the petioles in the uppermost ones short, but distinct : segments rather obtusely serrate, 

 the terminal ones more or less cordate or-*hombic-ovate. Umbels on peduncles 1-3 inches 

 long ; the rays, when in flower, less than an inch long, and little more than an inch when in 

 fruit. Calyx-teeth very small. Petals thick and somewhat succulent, very deep purple. 

 Styles slender, diverging. Fruit strongly winged, light brown with dark-colored intervals 

 when mature. 



Rocky hill-sides and borders of woods. Fl. June. Fr. August. 



♦ The name of the island was Thapsus or Thapsos, and had already l>ecn appropriated for another plant. It is to be 

 regretted that some other name had not been employed for the present genus. 



