VOL. II.] 



CARROT FAMILY. 



513 



1. O. filif prints. 



2. O. rigida. 



5. OXYPOLIS Raf. Neogen. 2. 1825. 



[TIEDEMANNIA DC. Mem. Omb. 51. 1829.] 



[ARCHEMORA DC. Mem. Omb. 52. 1829.] 



Erect perennial glabrous marsh herbs, from clustered tuberous roots, with pinnate or 

 ternate leaves, or in one species the leaves reduced to hollow jointed phyllodia, and com- 

 pound umbels of white flowers. Involucre none, or of a few linear bracts. Involucels of 

 several small bracts, or none. Calyx- teeth acute. Stylopodium thick, conic. Fruit gla- 

 brous, dorsally compressed, oval or obovate; dorsal and intermediate ribs slender, the lateral 

 ones winged, strongly nerved along the inner margin of the wing, the carpels appearing as 

 if equally 5-ribbed. Oil-tubes solitary in the intervals, 2-6 on the commissural side. Seed- 

 face nearly flat. 



Four known species, natives of North America. 

 Leaves all reduced to hollow usually jointed phyllodia. 

 Leaves pinnate; leaflets linear or lanceolate. 



i. Oxypolis filiformis (Walt.) Britton. 

 Oxypolis. (Fig. 2639.) 



O Enanthe filiformis Walt. Fl. Car. 113. 1788. 

 OEnanthe teretifolia Muhl. Cat. 31. 1813. 

 Tiedemannia terelifolia DC. Mem. Omb. 51. pi. 12. 1829. 

 Oxy polls filiformis Britton, Mem. Torr. Club, 5: 239. 1894. 



Stem hollow, 2-6 high. Leaves reduced to linear 

 hollow usually jointed acute phyllodia I'-iS' long; in- 

 volucre of several linear-subulate bracts; umbels 2 / -4 / 

 broad, 6-i5-rayed; rays slender, ^'-2' long; pedicels 

 2 // -4" long ; fruit oval, or slightly obovate, 2 // -3 // 

 long; oil-tubes large, i in each interval, 2-4 on the 

 commissural side. 



In ponds and swamps, southern Virginia to Florida, 

 west to Louisiana. Aug.-Sept. Plants collected in Dela- 

 ware, referred to this species, differ in having broadly oval 

 corky-winged fruit, an inconspicuous disk, slender conic 

 stylopodium and smaller oil-tubes. They may represent a 

 different genus. 



2. Oxypolis rigidus (L.) Britton. Cow- 

 bane. Hemlock, or Water Drop- 

 wort. (Fig. 2640.) 



Stum rigidum L. Sp. PI. 251. 1753. 

 Archemora rigida DC. Mem. Omb. 52. 1829. 

 T. rigida Coult. & Rose, Bot. Gaz. 12:74. 1887. 

 O. rigidus Britton, Mem. Torr. Club, 5: 239. 1894. 

 Rather slender, 2-6 high. Leaves petioled, 

 simply pinnate, the lower often i long or 

 more, the uppermost much reduced ; leaflets 

 thick, ovate-lanceolate, lanceolate or oblong, en- 

 tire, or remotely dentate, i #'-3' long, 3 // -i2 // 

 wide; involucre of 1-4 bracts, or none; umbels 

 2 x -4' broad, 7-25-rayed; rays slender, i / -4 / long; 

 pedicels 2 // ~9 // long; fruit oval, 2j // ~3 // long, 

 \Yz"-i" broad; oil-tubes small, i in each in- 

 terval, 4-6 on the commissural side. 



In swamps, New York to Florida, west to Wis- 

 consin, Minnesota, Missouri and Louisiana. Very variable in leaf- form and size of fruit. Aug. -Sept. 



Oxypolis rigidus longifolius (Pursh) Britton, Mem. Torr. Club, 5: 239. 1894. 

 Stum longifolium Pursh, Fl. Am. Sept. 194. 1814. 

 OEnanthe ambigua Nutt. Gen. i: 189. 1818. 



Leaflets elongated-linear, entire, i"-i l A" wide; fruit smaller. New Jersey to South Carolina and 

 Tennessee. ^ 



6. HERACLEUM L,. Sp. PI. 249. 1753. 



Erect, usually pubescent perennial herbs, with ternately compound leaves, and com- 

 pound umbels of white flowers. Bracts of the involucre few and deciduous, or none. In- 

 volucels of numerous linear bracts Calyx-teeth obsolete or small. Petals cuneate, or 

 clawed, those of the outer flowers dilated and obcordate or 2-lobed. Stylopodium thick, 

 conic. Fruit much flattened dorsally, broadly oval, obovate, or orbicular; dorsal and inter- 

 mediate ribs filiform, the lateral ones broadly winged and the wings nerved near the outer 

 margin; oil-tubes extending only to about the middle of the carpels, conspicuous, I in each 

 interval, 2-4 on the commissural side. [Greek, to Hercules.] 



About 60 species, natives of the northern hemisphere, only the following in North America. 



33 



