622 



AMMIACEAE. 



VOL. II. 



i. Eryngium aquaticum L. Rattlesnake- 

 master. Button Snakeroot. Fig. 3096. 



Eryngium aquaticum L. Sp. PL 232. 1753. 



E. yuccaefolium Michx. Fl. Bor. Am. i : 164. 1803. 



Stout, 2-6 high, glabrous ; stem sriate, simple, or 

 branched above. Leaves elongated-linear, acuminate 

 at the apex, mostly clasping at the base, finely 

 parellel-veined, the lower sometimes 3 long and li' 

 wide, the upper smaller, all with bristly margins, the 

 bristles rather distant ; heads stout-peduncled, globose- 

 ovoid, 6"-io" long, longer than the ovate or lanceo- 

 late cuspidate bracts ; bractlets similar to the bracts 

 but smaller; calyx-lobes ovate, acute; fruit scaly, 

 about i" long. 



In wet soil or upland, Connecticut to New Jersey, 

 Illinois, South Dakota, Florida, Kansas and Texas. 

 The name aquaticum is properly applied to this species, 

 ascertained by a study of the Linnaean type specimen. 

 June-Sept. Water-eryngo. Corn-snakeroot. Rattlesnake- 

 flag or -weed. 



2. Eryngium virginianum Lam. Vir- 

 ginian Eryngo. Fig. 3097. 



E. virginianum Lam. Encycl. 4: 759. 1797. 



Stem slender, erect, glabrous, branched 

 above, striate, i-3 high. Upper stem-leaves 

 linear, acuminate, sessile and clasping at the 

 base, 2'-8' long, spiny-toothed or rarely lacin- 

 iate, reticulate-veined ; basal and lower leaves 

 long-petioled, the blade linear-oblong, often 

 obtuse, entire, or remotely denticulate; heads 

 subglobose, 4"-?" long, equalling or shorter 

 than the lanceolate spiny-toothed or entire 

 reflexed bracts ; bractlets usually 3-cuspidate 

 with the middle cusp longest ; calyx-lobes lan- 

 ceolate, cuspidate ; fruit scaly. 



In marshes near the coast, New Jersey to Flor- 

 ida, west to Texas. July-Sept. 



3. Eryngium Leavenworthii T. & G. 

 Leavenworth's F.rvngo. Fig. 3098. 



E. Leavenworthii T. & G. Fl. N. A. i : 604. 1840. 



Stout, glabrous, i-3 high, branched above. 

 Stem-leaves sessile, or somewhat clasping at the 

 base, palmately pinnatifid into narrow spiny- 

 toothed segments ; basal and lowest leaves ob- 

 lanceolate, mostly obtuse, spinose-denticulate; 

 heads peduncled, ovoid-oblong, i'-2' long, nearly 

 i' thick, equalling or longer than the spinose 

 bracts ; bractlets 3-7-cuspidate, those of the upper 

 part of the heads large and resembling the bracts; 

 calyx-lobes pinnatifid, longer than the fruit. 



In dry soil, Kansas and Arkansas to Texas. July- 

 Oct. Briery thistle. 



