XJMBELLIFEE^. (PAESLEY FAMILY.) 195 



lanceolate, very sharply cut-serrate, with a wedge-shaped entire base ; flowers deep 

 yellow ;^i< oblong-oval, with 10 winged ridges. — Moist river-banks, &c. June. 



Var. ^pterum. Fruit witli strong and sharp ribs in place of wings. 

 (Smyruium aureum, L. Zizia aurea, Koch.) — With the winged form. 



4. T. trifoli^tum. Root-leaves or some of them round and heart-shaped; 

 stem-leaves simply ternate or quinate, or 3-parted; the divisions or leaflets ovate- 

 lanceolate or roundish, mostly abrupt or heart-shaped at the "base, crenately toothed; 

 flowers deep yellow ; fruit glohose-ovoid, with 10 winged ridges. — Rocliy thickets, 

 Vermont to Wisconsin, and southward : rare eastward. June. 



Var. atropurptireuni, Torr. & Gr. Petals deep dark-purple. (Thap- 

 sia trifoliata, L. Smyrnium cordatum, Walt. Thaspium atropurpureum, 

 Nutt.) — From New York westward and southward. 



Var. ^pterum. Petals yellow ; fruit with sharp ribs in place of wings. 

 (Zizia cordata, Koch, Torr.) With the preceding form. 



17. ZIZIA, DC. partly. (Zizia § TjenIdia, Torr. & Gr.) 



CaljTc-teeth obsolete. Fruit ovoid-oblong, contracted at the junction of the 

 carpels so as to become twin, the cross-section of each -seed nearly orbicular ; 

 carpels somewhat fleshy when fresh, with 5 slender ribs (which are more con- 

 spicuous when dry) : oil-tubes 3 in each interval and 4 on the inner face. — A 

 perennial smooth and glaucous slender herb (2° -3° high), with 2 - 3-ternately 

 compound leaves, the leaflets with entire margins ; umbels with long and slen- 

 der rays, no involucre, and hardly any involucels. Flowers yellow. (Named 

 for /. B. Ziz, a Rhenish botanist.) 



1. Z. integ^rrima, DC — Eocky hillsides : not rare. May, June. 



18. BUPLEUBUM, Tourn. THOEonoH-wAx. 



Calyx-teeth obsolete. Fruit ovate-oblong, flattened laterally or somewhat 

 twin, the carpels 5-ribbed, with or without oil-tubes. Plants with simple entire 

 leaves and yellow flowers. (Name from /SoCr, an ox, and jrXevpov, a rib.) 



1. B. EOTUNDiFOLiiiM, L. Leaves ovate, perfoliate ; involucre none; in- 

 volucels of 5 ovate leaflets. — Fields, New York to Virginia : rare. (Adv. 

 from Eu.) 



19. DISCOPLEtTRA, DC. Mock Bishop-weed. 



Calyx-teeth awl-shaped. Fruit ovoid ; the carpels each with 3 strong ribs on 

 the back, and 2 broad lateral ones united with a, thickened corky margin : in- 

 tervals with single oil-tubes. — Smooth and slender branched annuals, with the 

 leaves finely dissected into bristle-form divisions, and white flowers. Involucre 

 and involucels conspicuous. (Name from Sio-koj, a disk, and ir\fvp6v, a rib.) 



1. D. eapillicea, DC. Umbel few-rayed ; leaflets of the involucre 3 - 5- 

 cleft; involucels longer than the umbellets ; fruit ovate in outline. ^- Brackish 

 swamps, Massachusetts to Virginia, and southward. July -Oct. 



Var. '! QOStktU, DC. Larger; rays and divisions of the involucre numer- 

 ous ; ribs of the fruit stronger. — S. Illinois ( Vasey) and southwcstward. 



2. D. KuttWii, DC. Umbel many-rayed ; leaflets of the involucre eotire 

 and shorter ; fruit globular. — Wet prairies, Kentucky and southward. 



