184 PENTANDRIA. DIGYNIA. 



of the involucell are more numerous, acuminated, and 

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

 surrounded with 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. M. Lewis. 

 Flowering in April. Both these species exude a resinows 

 aromatic gum on incision, and also spontaneously in mi- 

 nute quantities. I have been induced to refer these 2 

 plants to tliis 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. 



£6r. PASTINACA. L. (Parsnip.) 



Fruit oval, apex emarginate, flatly (and dor- 

 sally) compressed, mari^inated, ridges (on each 

 seed) 5, obsolete, intervals striate, commissure 

 also bistriato. Involucrum universal and par- 

 tial, none. Sprengel. 



Flowers yellow; leaves pinnate. /*. sativa sometimes 

 produces involucells. 



Species. 1. 1-", sativa. /3. ar7:ensis. In Pennsylvania. 



A genus of about 5 species, indigenous to Europe and 

 the Levant. 



268. THAPSIA. L. 



*• Fnfi^ sublinear, eco&'tate; (seed) 4-winged, 

 wings 2 dorsal and 2 marginal. Involucrum 



Petals entire incurved; flowers yellow or white; leaves 

 twice or thrice pseudo-pinnate. 



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

 smooth and flat,c;uciately subbipinnatifid, segments linear- 

 oblong, obtuse, ultimate lobes confluent, subtrlfid; urabells 

 polygamo^'s, shorter than the leaves; involucrum none; 

 iBvolucell dimidiate; flowers numerous, subsessile. 



Sdinum acanle^ Pursh, 2. p. 732, in Suppl. v. s. in Herb. 

 Lambert, under this n.ame. 



Descript. Root tuberous, perennial. Plant smooth, 

 very low, almost steuiless andjdepresscd, sending up seve- 

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

 from the base, subdecumbent, only 4 to 6 inches high. 

 Leaves partly opposite, subbiternately divided, lobes short 

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



