162 UMBKLLIFER^. (PAKSLEY FAMILY.) 



9. DISCOPLEURA, DC. 



Calyx-teeth subulate, persistent. Fruit ovate ; the carpels strongly 3-ribbecl 

 on the back, and with two lateral ribs united with a thick corky margin. Inter- 

 vals with single vittse. — Smooth annuals, growing in marshes Leaves pin- 

 nately dissected, with the filiform divisions often whorled. Involucre and invo- 

 lucel conspicuous. Flowers white. 



1. D. capillacea, DC. Umbels .3 -10 rayed; leaves of the involucre 

 mostly 3-5-clcft; fruit ovate. (Ammi capillaceum, Michx.) — Brackish marsh- 

 es, Florida to Mississippi, and northward. June and July. — Stem 1° - 2° high, 

 much branched. Earliest leaves simple, or simply pinnate. 



2. D. eostata. Stem tali, branching above ; leaves of the involucre 10 - 

 1 2, many-parted ; fruit ovate, deeply sulcate. ( Ammi costatum, Ell. ) — Swamps 

 of the Ogcechee River, Georgia. October and November. — Stem 4° - 5° high. 

 Fruit larger than in No. 1 . 



3. D. Nuttallii, DC. Umbels many-rayed ; leaves of the involucre 5 - 6, 

 entire ; fruit globose. — Tampa Bay, Florida, and westward. — Stem 2° - 6° 

 high. 



10. HELOSCIADIUM, Koch. 



Calyx-teeth .5, or obsolete. Fruit ovate or oblong, flattened on the sides, the 

 carpels equally 5-ribbed. Intervals with single vittai. Flowers wiiite. 



1- H. nodiflorum, Koch. Stems prostrate or creeping ; leaves pinnate; 

 leaflets ovate-lanceolate, serrate ; umbels short-pedunded, opposite the leaves ; 

 involucre 1 - 2-leavcd or none; involucel 5-6-lcaved. (Sium nodiflorum, Zi.) 

 — Ditches, &c. around Cliarleston. Introduced. April -June. — Stems 2° 

 long. 



11. SIUM, L. 



Calyx-teeth small or obsolete. Fruit ovate or globular, flattened at the sides ; 

 the carpels with 5 equal corky ribs. Intervals usually with several vittse. — 

 Marsh or aquatic perennial herbs. Leaves pinnate ; the immersed ones dissected 

 into numerous capillary divisions. Involucre several-leaved. Flowers white. 



1. S. lineare, Michx. Leaflets varying from linear to oblong, finely and 

 sharply serrate ; calj-x-teeth minute ; fruit globular, strongly ribbed. — Along 

 streams, commonly in water, Florida to Mississippi, and northward. July. — 

 Stem 2° high. 



12. BUPLEURUM, Tourn. 



Calyx-teeth obsolete. Fruit flattened at the sides, or twin, ovate-oblong. 

 Carpels 5-ribbed, the inten-als with or without vitta;. — Smooth herbs, with en- 

 tire simple leaves, and yellow flowers. 



1. B. rotundifolium, L. Leaves ovate, perfoliate ; umbel 5-rayed ; in- 

 volucre none ; leaves of the involucel 5, ovate, mucronate. — Fields, North Caro- 

 lina. — Introduced. 



