184 FENTANDRIA. DIGYNIA, 



of the involucell are more numerous, acuminated, and 

 divided down to the base; the seeds are elliptic-ovate, 

 surrounded witlv a narrower marg^in; the petals white, 

 oblong and involute at the point — Hab. With the above; 

 also on the plains of the Columbia river. J\f. Lewis. 

 Flowering in April. Both these species exude a resinous 

 aromatic gum on incision, and also spontaneously in mi- 

 nute quantities. I have been induced to refer these 2 

 ])lants to this genus rather than any other with which 1 

 am acquainted, though they differ considerably in habit, 

 but agree with the Ferula pumila of Pallas, indigenous 

 to Siberia. 



267. PASTINACA. L. (Parsnip.) 



Fruit oval, apex emarginatc, flatly (and dor- 

 sally) compressed, marginated, ridges (on each 

 seed) 5, obsolete, intervals striate, commissure 

 also bistriate. Iiivolncnim universal and par- 

 tial, none. Sprengel. 



Flowers yellow; leaves pinnate. P. sativa sometimes- 

 produces invoiucells. 



Species. 1. P. sativa. /3. arvensis. Tn Pennsylvania. 



A g-enus of about 5 species, indigenous to Europe and 

 the Levant. 



268. THAPSIA. L, 



«-Fr?(t'^ sublinear, ecostate; (seed) 4-\vinged, 

 v;ings 2 doi'sal and 2 marginal. Inrolucrum 

 none." Sprkkgei.. 



I'etals entire ii^.curvcd; flowers yellow or white; leaves 

 twice ortlirico pseudo-pinnate. 



Species. 1. T. *gIornernia. Nearly stemless; leaves 

 smooth und flitt,cruciately subbipinnatifid, segments linear- 

 oblong, obtuse, ultimate lobes confluent, sidnrifid; umbells 

 pol} 5::iimous, shorter than the leaves; involucrum none; 

 involucell dimidiate; flowers numerous, subsessile. 



S'linvm acan^c, Pursi), 2. p. 732, in Suppl. v. s. in Ileib. 

 Lambert, under this name. 



Descript. Root tuberous, pereimial. Plant smooth, 

 very low, almost stenikss and depressed, sendiiig up seve- 

 ral stalks from the same root; stem simple, or subelivided 

 from the base, subdeciimbent, only 4 to 6 inches liigli. 

 Leaves partly op[)osite,subbiternately divided, lobes short 

 and obtuse, decussatijig at the base; petiole as long as 



