PEXTAXDRIA DIUYXIA 195 



1. A. rtgida, DC. Stem rigid, striate; leaves pseudo-pinnate, smooth; 

 leaflets 3 to 5 pairs with a terminal odd one, oblong-lanceolate, very 

 entire, or remotely and sparingly inciscd-dentate near the apex, sessile; 

 umbels spreading, terminal and subterminal, smooth, on long pedun- 

 cles. Beck, Bot. p. 148. 



Also? A. tricuspidata. DC. Prodr. 4. p. 188. 



Sium rigidius. WilUL Sp. 1. p. 1433. Pers. Syn. I. p. 316. Ait. Kew. 2. 

 p. 145. Muhl. CataLp. 31. Pureh,Am. l.p. 194. EU. Sk. l.p. 353. 

 S. rigid um. ZdndU Ency. p. 216. 



8. Iongifolium. Floral. Cesir. p. 34. not of Pursh. 

 Also ? 8. tricuspidatum. Ell. Sh. l.p. 354. 



Sison marginatum. JJfr. Am. l.p. 168. Also, Per*. Syn. l.p. 317. 



Muhl. CataLp, 34. Pursh, Am. l.p. 194. 



CEnanthe rigida. Nutt. Gen. 1. p. 1S9. Bart. Phil. l.p. 142. Eat. 



J fan. p. 237. 



Pastinaca rigida. Torr. Fl. l.p. 314. Ejusd. Comp. p. 137. 



Rigid, or stiff Archxmoba. Yulgd — Cow-banc. 



Root perennial. Stem 2 to 4 or 5 feet high, slender, erect, rigid, terete, striate, 

 finootb, slightly branched atsummit. Leaves n\\ simply pseudo-pinnate ; petioles 

 i to 5 or 6 inches long, channelled and somewhat margined. Leaflets usually in 8 

 •r 4 pairs, with a terminal odd one, 2 to 3 or 4 inches long, and one fourth to half 

 an inch, and sometimes 3 quarters, in width, varying from linear-lanceolate to 

 lance-oblong, and cunoale-oblanceolate, often a little falcate, acute, sessile, some- 

 what rL'M. circumscribed by a narrow whitish slightly scabrous margin, sunt tim^s 

 v-jry entire, often with 1 to 3 or 1 Longish acute incised leeth on each side near lh« 

 apex (frequently m ire teeth on one side th in on the other), and occasionally the 

 leaflets are so deeply inci das to a I ciniatc. Umbels about 3, on rather 



long sulcate-slr iate pedun ! s ; i I n ler, l to 2 ini h iB long. Involucre mostlj 



9, sometimes of2or31ance-lincar I. aves. />iro/ace/.«of6 or 8 linear-subulate leaver, 

 shorter than the rays of the umbel lets. ( alyx with 5 acute teeth, or sometimes ob- 

 solete ? Petals white, apparently emarginate, or obcordate, by the inflexion of the 

 apex. Fruit elliptic-ovate, with con vex acute and apparently simple margins, 

 moderately compressed and convex on the back (flat, Nutt. much compressed* 

 Torr.), crowned with the dilated subconic base of the short diverging sii/Ies. Car- 

 pels with 5 nearly equal llattish equidistant greenish ribs, the lateral ones dilated 

 into a snberose marginal wing with a thin edge ; inlets'iccs convex, dark purple. 

 Commissure, or face, a little concave, lined with a whitish suberose coat. Seed 

 elliptic, acute at each end, piano-convex, ribbed on the back. 



Hab. Low, swampy grounds : frequent. Fl. Aug. jFV. Sept.— Octo. 



Obs. This plant is believed to be an active poison,— particularly ton »rn d eat. 

 Me, when eaten by them ; and therefore ought to be eradicated from all pastor* s. 

 Two or three additional species are enumerated in the U. States. 



150. PASTINACA. L. Nutt. Gen. 267. 

 [Latin, Pastus, a repast, or nourishment ; from the use made of the root ] 



Calyx with the limb obsolete, or minutely denticulate. Petals round- 

 ish-ovate, involute, with a broadish retusc incurved apex. Fruit ova], 

 flatly compressed on the back, with a dilated flat margin. Carpels 

 with 5 very slender ribs ; 3 of them dorsal, and ©quidistant ; the 2 



