278 UMBELLIFER^. Archemora. 



1. Archemora rigida, DC. (Plate xxxvi.) Rigid-leaved Arche?nora. 



Leaves pinnately divided. — DC; Torr. <^ Gr. Jl. N. Am. 1. />. 631. 



var. 1 . Segments of the leaves ovale, oblong or lanceolate, remotely toothed or denticulate, 

 often entire. Torr. <^ Gr. I. c. A. rigida, tricuspidata and denticulata, DC. I. c. A. rigida. 

 Beck, hot. p. 148; Darlingt. ft. Cest. p. 195. Slum rigidius, Linn. sp. 1. p. 251. S. 

 rigidius, tricuspidalum and dcnticulatum, Ell. sk. 1. p. 354. Sison marginatum, Michx. 

 jl. \. p. 168 ; Pursh,jl. \.p. 194. ffinanthe rigida, Nutt. gen. \.p. 189. Pastinaca rigida, 

 Spreng. in Schult. syst. 6. p. 586 ; Torr. fl.\. p. 314. 



var. 2. Segments of the leaves linear, elongated, mostly entire. Torr. ^- Gr. I. c. A. 

 ambigua, DC. I. c. ; Beck, I. c. Slum longifolium, Pursh, Jl. l.p. 194. (Enanthe ambigua, 

 Nutt. I. c. Pastinaca ambigua, Spre?ig. I. c. ; Torr. I. c. 



Root fasciculate, fleshy. Stem 2-5 feet high, erect, slender but somewhat rigid, terete, 

 striate. Leaves light green, with 2-5 pairs of leaflets, of a firm texture : in the first variety, 

 from half an inch to more than an inch wide, the teeth few and remote, or often wholly wanting; 

 in the second form, only 2-4 lines wide, and seldom toothed. Umbels usually 3 on each 

 plant ; the rays numerous and slender. Fruit about 3 lines long, broadly elliptical, greenish- 

 yellow, the ribs slightly elevated : intervals dark purple : commissure white. 



Swamps ; western part of the State ; rare. Fl. August. Fr. September - October. The 

 two varieties often grow together, and pass into one another. The plant is generally supposed 

 to be highly poisonous. 



15. PASTINACA. Tourn. ; Endl. gen. Ai73. parsnep. 



[ Name derived from the Latin, pnstus, food.] 



Calyx-teeth obsolete or minute. Petals somewhat orbicular, entire, involute ; the point broad 

 and retuse. Fruit much compressed, with a dilated flat margin. Carpels with 5 very 

 slender ribs ; 3 of them dorsal and equidistant ; the lateral ones remote, and contiguous to 

 the margin. Intervals with single vittae. Commissure with 2 or more vittas. Carpophore 

 2-parted. Seed flat. — Perennial or biennial herbs, with fusiform often fleshy roots. Leaves 

 pinnately divided ; the segments toothed, incised or lobed. Involucre and involucels few- 

 leaved or none. Flowers yellow. 



1. Pastinaca sativa, Linn. Co7nmon or Wild Parsnep. 



Stem sulcate, smooth ; leaves minutely pubescent ; segments ovate-oblong, obtuse, un- 

 equally toothed and serrate, cut at the base, the terminal one 3-lobed ; fruit oval, the com- 

 missure with 2 vittae. — Linn. sp. 1. p. 262 ; Engl. hot. t. 556 ; Pursh, Jl. 1. p. 196 ; Torr. 

 Jl. 1. p. 314 ; Bigel. Jl. Bost. p.lVd; DC. prodr. 4. p. 188 ; Darlingt. Jl. Cest. p. 196 ; 

 Torr. «J- Gr. Jl. N. ylm.l. p. 632. 



