0:{ 



JLs langc o\orla|i.s with lliiit i>f f/v. >!ti niiciiloHii, while tiic leaf oliaiaolors 

 depended upon to distinguisli it are not constant, but show cv*'!}- gradation 

 to the leaf characters of that species. 



•is. CVXOSCIADII'I.I DC. Mem. rinl)c-l. 44. (ilahrous 

 annuals, with pinnatcly (li\itleil caulinc leaves (leaflets linear), 

 mostly undisi'lcd lower and ladical lea\ es, involucre and invol- 

 ucels of linear luacts, and white (lowers. 



1. C. digitatum DC. 1. c. Slender, 1 to 2 feet hig^h: radi- 

 cal leaves linear-lanceolate, entire; caulinc leaves palmatcly 3 to 

 r)-parted: umbels irregular, mostly ){ to 8-rayed; rays about an 

 inch long; pedicels ver\' une(|ual, '4 to 1(1 lines long: fruit a line 

 long, contracted into a neck at summit, with very prominent ribs 

 and minute calvx-teeth. (I'ig. 101.) 



Wot ground. Arkansas. Alahania, Louisiana, and Texas Fl May and 

 June. 



~. C. pinnatum DC. 1. c. Smaller: cauline leaves pinnately 

 divided into few distant segments, terminal one much the largest; 

 radical leaves similar or often entire: umbels 5 to l(.)-rayed; rays J/4 

 to 1 inch long; pedicels 1 to 4 lines long: fruit li^ lines long, not 

 beaked at summit, with less prominent ribs and very j^rominent 

 calyx-teeth.' (Fig. 102.) 



Wet ground, Arkansas, Indian Territory, and Texas. Fl. April. 



Quite variable in size, often becoming very low and passing into 



Var. pumilum Engfdm. tK: Gray, PI. Lindh. 10, which is a 

 cespitose form. 

 Texas. 



2U. ERYNGIUM Linn. Gen. n. 824.— Glabrous peren- 

 nials, with leaves mostly rigid, coriaceous, spinosely toothed or 

 divided, and white or blue flowers sessile in dense bracteate heads. 



The outer bracts form the involucre, the inner ones, bractlets^ 

 intermixed with the flowers, represent the involucels. (Fig. 1(^8.) 



* Stoxt^ xv/'t/i fia rail el -veined elongated linear coriaceous 

 leaves^ iL'hic/i arc mostly entire or ~L'it1i niaroiti sparingly bristly: 

 extending- north ward. 



1. E. yuccaefolium Michx, Fl. i. 104. From 1 to (i feet 

 high, branching alcove: leaves broadly linear (from 2 lines to over 

 an inch wide), tapering to a point, with remotely bristly margins. 



